AUL   B.   HOEBER    j 
MEDICAL     BOOKS 
3    EAST    59    TH    ST. 


MEDICAL    *SCH<0>€>L 


a  N 


THE  THEORY  OF  IONS 


THE 

THEORY  OF  IONS 

A  CONSIDERATION  OF  ITS  PLACE 
IN  BIOLOGY  AND  THERAPEUTICS 


BY 


WILLIAM 

M.D.  (Hon.  Causa)  CHICAGO,  LL.D.,  L.E.C.P.E.,  M.B.C  S., 

L.S.A.,  BTC. 
AUTHOR  OF  "  FOOD  AND  HYGIENE,"  ETC. 


NEW   YORK 

REBMAN    COMPANY 
1123    BROADWAY 


Entered  at  Stationers  Hall.     All  rights  reserved 
by  Rebman  Limited,  London. 


4-3 


PREFACE 


TIME  was  when  the  earth  was  supposed  to  be  fixed 
and  have  a  flat  surface,  when  the  sun  revolved 
around  the  earth,  and  the  moon  as  a  luminary  shed 
forth  its  own  light.  Time  was  when  dryads  and 
fauns  dwelt  in  our  forests,  when  fairies  tripped  upon 
the  greensward,  and  mermaids  sang  in  the  ocean. 
Time  flies,  customs  change,  and  knowledge  pro- 
gresses. We  know  now  that  the  earth  is  not  flat, 
the  moon  is  not  a  resplendent  orb,  that  fairies  do 
not  dance  upon  our  lawns.  Among  the  many 
theories  of  the  earth's  origin  none  was  so  fiercely 
fought  as  the  nebular  hypothesis,  of  man's  origin 
none  caused  such  bitter  antagonism  as  the  evolu- 
tionary theory,  but  both  are  now  accepted  by  the 
majority  of  men  capable  of  considering  their  mean- 
ing. One  of  the  most  popular  ideas,  one  which 
persists,  and  which  our  ever-increasing  knowledge 
has  not  changed,  is  that  there  are  only  two  forms 
of  matter,  inorganic  and  organic  or  dead  and  living 
matter.  It  is  supposed  that  there  is  no  condition 
between  ;  a  thing  is  either  living  or  it  is  dead,  it 
must  be  one  or  the  other.  In  the  gross  this  is  true. 
There  is  a  mighty  gulf  between  the  living  and  the 
dead.  But  how  can  we  be  sure  that  there  is  no  inter- 
mediate condition  ?  The  question  of  Biogenesis 

v 

1818 


vi  PREFACE 

presents  many  difficulties,  and  the  way  of  their 
solution  is  not  yet  apparent.  Scientific  experience 
has  been  unable  to  establish  the  fact  of  Abiogenesis 
or  spontaneous  generation  to  the  satisfaction  of 
many  minds.  Some  men  of  note  accept  Abiogenesis 
willingly,  and  claim  to  have  proved  it.  Many  others 
have  sought  evidence  which  would  convince  them 
of  its  possibility  and  probability,  and  would  gladly 
be  convinced,  but  they  have  failed  to  get  the  living 
from  the  dead,  and  have  said  that  the  doctrine  of 
Biogenesis,  or  Life  can  only  come  from  Life,  was 
victorious  all  along  the  line.  The  passage  from  the 
inorganic  to  the  organic  world,  from  the  dead  to  the 
living,  appears  to  be  barred.  No  change  of  substance, 
no  chemistry,  no  transformation  of  energy,  has  ever 
yet  endowed  any  single  atom  with  vitality.  Such 
is  the  argument.  Huxley  admitted  that  the  present 
state  of  our  knowledge  furnishes  us  with  no  link 
between  the  living  and  the  not-living.  Bastian's 
experiments  on  the  Beginning  of  Life  have  failed  to 
satisfy  the  minds  of  most  men.  Is  there  any  middle 
course,  any  other  way  between  the  theories  of  Bioge- 
nesis and  Abiogenesis  ?  Energy  is  capable  of  trans- 
formation from  one  form  to  another ;  potential  energy 
becomes  kinetic  energy.  Evolution  is  evidenced  in 
many  things  which  are  not  associated  with  tho 
development  of  animals.  It  is  thought  that  even 
matter  is  not  constant,  but  that  developmental 
changes  take  place  in  it.  We  know  that  a  diamond 
and  a  piece  of  charcoal  are  both  composed  of  carbon  ; 
the  diamond  must  have  undergone  much  transforma- 
tion if  it  ever  had  the  characteristics  of  charcoal. 
The  transmutation  of  the  metals  was  a  desideratum 


PREFACE  vii 

of  the  Alchemists  ;  and  such  transformation  is  pos- 
sible, even  though  it  be  not  in  the  way  they  desired. 
May  not  the  evolution  theory  be  applied  to  matter 
which  becomes  organic  ?  The  touch  of  life  is  neces- 
sary to  give  life  !  Life  is  apparently  not  conferred 
upon  raw  and  inert  matter,  but  upon  such  com- 
pounds as  are  prepared  for  it,  such  substances  as 
have  been  evolved  from  the  inorganic  to  the  organic. 
This  view  is  held  by  the  author.  Life  is  to  him  a 
gradual  growth,  a  gradual  transformation  from  the 
dead  to  the  living  by  evolution,  a  change  of  char- 
acter, step  by  step,  until  from  the  crude  elements 
of  the  earth,  air  and  water,  there  is  evolved  the 
motile  and  sentient  substances  which  form  our 
muscles  and  nerves.  Natura  nihil  facit  per  saltum. 

The  point  of  view  here  taken  necessitates  the 
existence  of  intermediary  substances  between  the 
living  and  the  not-living  matter — substances  pos- 
sessed of  qualities  akin  to  the  properties  of  living 
matter.  The  process  of  ionisation  appears  to  the 
author  to  confer  some  of  those  properties.  The 
atoms  become  quick,  they  are  no  longer  inert,  but 
they  are  capable  of  forming  molecular  combina- 
tions ;  they  have  movement,  affinity,  energy.  The 
living  materials  of  an  organism  consist  of  com- 
pounds of  carbon,  hydrogen,  oxygen,  and  nitrogen, 
which  have  plasticity  and  a  capacity  for  living. 
Such  compounds  are  not  drawn  directly  from  in- 
organic materials,  but  their  growth  into  carbo- 
hydrates, fats,  and  proteins  is  a  gradual  process  of 
chemical  development  or  evolution.  The  proteins 
are  formed  of  compounds  of  amino-acids,  which 
have  been  evolved  from  simpler  bodies  contain- 


viii  PREFACE 

ing  the  necessary  elements.  In  each  of  these 
changes  the  substance  becomes  more  plastic,  but 
more  unstable ;  more  nearly  living,  but  more  easily 
decomposed. 

In  the  author's  view  of  the  origin  of  the  living 
from  non-living  substances  the  ionisation  of  materials 
and  formation  of  meres  takes  a  great  part.  The 
formation  of  ions  is  observed  in  many  ways.  It 
occurs  both  in  growing  and  disintegrating  tissues. 
It  is  observed  in  dead  as  well  as  in  living  substances. 
Some  of  the  observed  facts  have  been  noted  in  the 
following  pages,  in  which  an  endeavour  has  been 
made  to  place  the  theory  of  ions  before  the  reader, 
and  to  show  that  ions  occupy  an  important  place  in 
biological  processes.  The  continuous  adjustment 
of  the  internal  relations  of  materials  to  the  external 
relations  is,  in  the  author's  view  of  the  subject, 
brought  about  by  the  ionisation  of  matter,  the 
transformation  of  energy,  and  the  definite  com- 
bination of  these  heterogeneous  changes,  both  simul- 
taneous and  successive;  and  these  "in  correspon- 
dence with  external  coexistences  and  consequences  " 
result  in  the  development  of  the  dead  into  the  living, 
the  inorganic  into  the  organic. 

W.T. 

NOTTINGHAM. 


CONTENTS 


8ECTION 


I.  —  INTRODUCTION  -  .  1 

II.  —  THE  IONS         -  -  12 

III.—  IONS  IN  BIOLOGY  .  30 

IV.—  EVOLUTION  OF  ORGANIC  MATTER       -  -  46 

V.—  INFLUENCE  OF  IONS  ON  THE  ORGANISM  -  80 

VI-  —  THE  INFLUENCE  OF  IONS  IN  OXIDATION  AND 

IMMUNISATION  . 


IX 


THE  THEORY  OF  IONS 

I.—INTKODUCTION 

MATTER  is  subjected  to  a  variety  of  chemical  and 
physical  changes.  Any  change  which  matter  under- 
goes without  destroying  its  integrity  is  regarded  as 
physical ;  but  any  change  which  involves  a  structural 
alteration  of  its  molecules  is  chemical.  Matter  is 
unstable  ;  change  is  constantly  occurring.  Life  is 
the  result  of  many  changes  in  matter,  by  which  it 
is  organised,  becomes  motile  and  sentient. 

According  to  the  Atomic  theory  all  matter  consists 
of  particles  so  infinitesimal  as  to  admit  of  no 
division.  These  are  the  first  principles  or  com- 
ponents of  all  bodies.  They  unite  atom  with  atom 
or  in  proportion  of  some  simple  multiple  of  atoms 
to  form  molecules.  Molecules  are  the  smallest 
particles  of  matter  which  exist  in  a  free  and  inde- 
pendent state  ;  they  consist  of  two  or  more  atoms  of 
one  or  more  kinds  of  matter. 

Matter  and  force  are  changeable  but  indestructible, 
and  there  are  two  chief  theories  in  respect  of  them. 
According  to  the  kinetic  theory  of  substance,  the 
atoms  are  separate  dead  particles  of  matter  which 
dance  to  and  fro,  and  act  upon  other  particles  of 

1 


2  THE  THEORY  OF  IONS 

matter  at  a  distance  ;  they  constantly  encounter 
and  rebound  from  one  another,  some  moving  with 
a  greater  or  less  speed  than  others,  but  all  having 
an  average  velocity.  In  these  encounters  there  is 
no  loss  of  energy  so  long  as  the  temperature  remains 
the  same,  for  every  action  is  balanced  by  an  equal 
and  contrary  reaction  ;  but  any  change  of  tempera- 
ture causes  a  change  of  velocity,  with  increased  speed 
there  is  increased  heat  and  some  of  the  energy 
then  radiates  into  space.  This  vibratory  motion  of 
the  smallest  particles  of  matter  is  regarded  by  many 
authorities  as  the  fundamental  exhibition  of  the 
energy  stored  up  in  matter  ;  and  attraction,  gravity, 
chemical  action,  magnetism,  electricity,  heat  and 
light  are  regarded  as  being  modifications  of  the 
primitive  inherent  force. 

According  to  the  brilliant  theory  of  J.  C.  Vogt, 
spate  is  filled  with  a  fundamental  force,  and  its 
activity  is  shown  by  a  tendency  to  the  condensation 
of  matter,  which  produces  infinitesimal  centres  of 
attraction.  In  this  theory  of  condensation,  however, 
the  separate  particles  are  credited  with  sensation 
and  inclination,  a  will-movement  of  the  simplest 
form.  Centres  of  disturbance  occur  which  posi- 
tively exceed  the  mean  tendency  to  condensation, 
whence  are  formed  the  ponderable  matter  of  bodies  ; 
centres  of  disturbance  also  occur  which  negatively 
fall  below  the  mean  power  of  condensation,  and 
these  form  the  ether  or  imponderable  matter. 
Positive  or  ponderable  matter,  ever  straining  to  com- 
plete the  process  of  condensation,  collects  an  enor- 
mous amount  of  potential  energy  ;  negative  or  im- 
ponderable matter  (the  ether)  offers  a  perpetual 


THEORIES  OF  MATTER  3 

resistance  to  the  further  increase  of  its  strain,  and 
thus  gathers  the  utmost  amount  of  actual  or  kinetic 
energy. 

According  to  the  former,  the  kinetic  or  vibration 
theory,  the  atoms  of  each  molecule  are  regarded  as 
being  in  a  state  of  motion  towards  each  other,  that 
is  in  the  system  of  the  molecule  ;  but  the  molecule 
alone,  that  is  a  whole  system  of  atoms,  performs 
independent  movements.  In  the  latter  or  condensa- 
tion theory  the  pyknatoms,  which  correspond  to  the 
separate  atoms  of  the  vibration  theory,  are  con- 
sidered to  have  will-power  and  to  be  independent. 
Whichever  theory  we  incline  to,  matter  consists  of 
atoms  which  are  always  associated  with  energy  and 
are  formed  into  molecules.  Each  atom  or  molecule 
exhibits  activity  towards  other  atoms  or  molecules, 
the  general  tendency  of  which  is  shown  by  attraction 
or  gravity,  or,  according  to  the  theory  of  Vogt,  by 
condensation. 

Atoms  are  the  smallest  particles  of  matter  which 
can  take  part  in  a  chemical  action.  In  every 
chemical  action  there  is  a  rearrangement  of  the 
energy  as  well  as  the  matter.  When  water  is  boiled 
it  is  transformed  into  steam,  but  the  molecules  are 
not  altered,  when  the  steam  is  cooled  it  is  water 
still.  If,  however,  the  heat  is  applied  in  a  greater 
degree,  as  by  passing  electric  sparks  through  the 
steam,  there  is  a  great  change  in  the  nature  of  the 
material,  it  does  not  condense  when  it  is  cooled, 
but  the  water  is  disintegrated,  and  in  place  of 
each  molecule  we  have  two  atoms  of  hydrogen  and 
one  of  oxygen.  The  nascent  atoms  of  H  and 
0,  into  which  the  compound  molecule  has  been 

1—2 


4  THE  THEORY  OF  IONS 

dissociated,  are  charged  with  electricity  and  move 
about ;  such  dissociated  atoms  are  called  ions. 
Whenever  a  change  occurs  in  the  constitution  of 
molecules  consisting  of  similar  or  diverse  material 
such  ions  constitute  the  nascent  material.  They 
consist  of  one  or  more  elements,  and  part  at  least 
of  the  associated  energy  is  in  the  form  of  electricity. 
In  a  fluid  or  gas  which  is  undergoing  dissociation, 
the  ions  or  dissociated  particles  are  in  a  state  of 
rapid  movement,  and  their  velocity  varies  more  or 
less  with  the  temperature  and  other  conditions. 
Their  movements  are  infinitely  complicated  owing 
to  the  impaction  of  the  ions  one  against  another, 
some  having  a  velocity  greater  than  others  and 
consequently  a  higher  temperature.  There  is 
however  a  mean  velocity  and  temperature  through- 
out the  particles,  and  a  mean  free-path ;  and 
although  the  rate  of  velocity  differs  for  ions  of  differ- 
ent kinds,  ions  of  the  same  elements,  under  the  same 
conditions,  travel  at  the  same  rate. 

Much  as  we  know  about  matter,  our  knowledge 
is  finite,  and  it  is  certain  that  our  present  knowledge 
is  incomplete.  The  discovery  of  new  elements  has 
shown  that  there  are  forms  of  matter  whose  existence 
until  recently  was  unsuspected  ;  that  matter  exists 
from  which  force  emanates  in  such  a  manner  as 
to  show  the  close  relationship  of  matter  and  force. 
Some  of  these  elements  shed  forth  energy  so  long 
as  they  endure,  and,  inert  as  they  are  chemically, 
their  radio-activity  is  enormous.  Much  speculation 
about  the  nature  of  radio-activity  and  much  ex- 
perimental work  has  not  yet  solved  the  mystery 
of  the  energy  which  emanates  from  such  materials 


THEORIES  OF  MATTER  5 

as  radium,  uranium  and  thorium.  We  know  that 
the  emanations  are  powerful,  and  that  they  are  not 
of  a  simple  character,  for  the  "  radiations  "  consist 
of  separable  emissions.  Among  these  are  what  are 
known  as  the  a  rays,  which  consist  of  particles  of 
matter  sent  forth  with  an  enormous  velocity,  highly 
charged  with  positive  electricity  and  capable  of 
producing  the  ionisation  of  gases.  The  particles  of 
matter  forming  these  emanations  are  considered  by 
physicists  to  differ  from  the  chemical  atom  and  are 
called  primary  atoms,  corpuscles,  electrons  and 
metabolons.  Whatever  their  nature  may  be,  they 
appear  to  be  similar  to  the  ions  dissociated  from 
matter  in  many  ways,  and  they  are  charged  with 
such  an  amount  of  energy  as  to  be  phosphorescent. 
When  solid  radium  nitrate  is  brought  near  to  a 
suitable  screen,  the  latter  is  seen  to  be  dotted  all 
over  with  brilliant  specks  of  light  (visible  through  a 
lens)  due  to  "  the  bombardment  of  the  screen  by 
the  electrons  hurled  off  by  the  radium."  Among 
the  emanations  are  /3  rays,  which  also  consist  of 
matter  projected  with  a  high  velocity,  charged  with 
negative  electricity,  and  having  properties  similar 
to  the  cathode  rays  emitted  from  a  vacuum  tube. 
But  the  emissions  from  radio-active  bodies  do  not 
all  consist  of  matter,  for  there  are  7  rays  which  con- 
sist of  a  wave-like  motion  similar  to  light,  and  are 
probably  an  exhibition  of  energy  emitted  from  the 
material. 

Experiments  have  shown  that  radio-active  bodies 
owe  their  activity  to  atomic  changes  in  the  material, 
that  the  atoms  of  such  materials  are  undergoing 
disintegration,  that  in  their  movements  such  atoms 


6  THE  THEORY  OF  IONS 

have  their  energy  transformed  into  exhibitions  of 
force  of  a  very  high  character,  and  that  as  the  atoms 
break  up  some  of  the  matter  with  its  accompanying 
kinetic  energy  is  thrown  off  in  the  form  of  electrons 
or  metabolons. 

It  is  the  "  internal  energy  stored  up  in  the  chemical 
atom  "  which  is  set  free  during  radio-activity,  and 
it  is  of  far  greater  magnitude  than  that  exhibited 
during  chemical  changes. 

The  conception  of  an  atom  as  a  system  is  contrary 
to  preconceived  ideas  of  the  nature  of  matter  ;  and 
the  idea  that  atoms  may  become  disintegrated  gives 
a  new  view  to  our  conception  of  matter.  It  has 
hitherto  been  considered  that  an  atom  was  the  lowest 
stage  in  the  composition  of  an  element ;  but  if  the 
knowledge  gained  from  radio-activity  proves  to  be 
correct,  we  have  exhibited  to  us  the  fact  that  the 
elements  themselves  may  disintegrate.  Although 
atoms  are  chemically  the  lowest  stage  of  matter,  yet 
physically  such  atoms  undergo  changes,  and  such 
changes  indicate  that  there  may  be  an  evolution  of 
matter,  that  such  evolution  consists  in  the  trans- 
formation of  elements  of  one  atomic  weight  into 
elements  of  a  different  atomic  weight  and  exhibiting 
different  characteristics.  The  work  of  Crookes, 
Wendt,  Preyer  and  others,  leads  to  the  assumption 
that  the  elements  are  not  the  simple  homogeneous 
and  unchangeable  materials  we  previously  con- 
sidered them  to  be  ;  but  that  they  are  compounds 
of  atoms  whose  systems  consist  of  different  numbers 
and  various  groups  ;  that  the  seventy  substances 
known  and  believed  to  be  elements  may  be  arranged 
into  eight  groups,  and  the  arrangement  of  such 


CHARACTERS  OF  LIVING  MATTER        7 

groups  suggests  their  evolution  from  one  primitive 
substance,  the  prothyl. 

The  evolution  of  matter  also  includes  the  evolution 
of  energy  ;  indeed,  the  unity  of  natural  forces  on 
the  basis  of  a  common  origin  is  accepted  by  most 
competent  authorities.  The  transformation  of  energy 
into  various  exhibitions  of  heat,  light,  electricity, 
and  other  forces  has  long  been  known.  It  is  known 
also  that  such  exhibitions  are  accompanied  by  wave- 
like  motions,  which  vary  in  their  length  and  rapidity 
in  accordance  with  the  form  of  energy  displayed. 
Emanations  from  radio-active  bodies,  in  which  the 
atoms  are  undergoing  disintegration,  are  called 
electrons  or  metabolons,  and  the  total  energy  asso- 
ciated with  such  emanations  is  almost  incalculable. 
When  molecules  of  matter  disintegrate  there  is  a 
similar  display  of  energy  from  the  disintegrated 
matter  ;  the  materials  resulting  from  such  disin- 
tegration are  called  ions,  the  associated  energy  is 
chiefly  exhibited  as  heat  or  electricity,  and  in  many 
instances  the  amount  is  ascertainable.  In  both 
instances  we  have  matter  disorganised  and  ready  for 
reorganisation.  In  both  instances  we  have  an  exhibi- 
tion of  the  very  close  relationship  of  matter  and  force ; 
evidence  that  matter  does  not  exist  without  force. 
In  ions  and  metabolons  we  see  matter  in  a  state 
intermediate  between  the  inert  substance  of  the 
earth  and  the  living  matter  of  an  organism.  As 
matter  may  undergo  evolution,  and  the  transmuta- 
tion of  common  elements  into  the  highly  valued  and 
rarer  metals  may  ultimately  fulfil  the  dreams  of  the 
alchemists  ;  so,  on  the  other  hand,  we  may  find  that 
ions,  which  are  particles  of  matter  far  more  gross 


8  THE  THEORY  OF  IONS 

than  those  emitted  from  radio-active  bodies,  are  so 
constituted  as  to  be  not  only  the  connecting-link 
between  the  physically  inert  particles  of  a  gross 
material  and  the  living  molecules  of  an  organised 
system,  but  that  they  are  materials  already  on  their 
way  to  form  new  chemical  substances.  We  may 
find  that  ions  derived  from  chemically  organic  sub- 
stances, hitherto  classed  as  dead  matter,  already 
exhibit  some  of  the  characteristics  of  living  matter. 
It  is  not  considered  that  ions  are  actually  living 
substance  ;  but  that  they  are  in  a  condition  in  which 
the  characteristics  of  vital  matter  may  readily  be 
developed.  We  may  find  that  the  process  of 
vitalising  matter  is  evolutionary.  That  life  is  not 
conferred  upon  gross  inorganic  matter,  but  the  living 
matter  assimilates  ions  of  various  kinds,  and  that 
ions  alone  constitute  matter  which  is  ready  for 
organisation. 

The  only  chemical  compounds  which  are  peculiar 
to  living  substance  or  protoplasm  are  the  group  of 
albuminoids  ;  and  the  only  element  which  is  capable 
of  building  up  these  albuminoids  is  carbon.  All  the 
albuminoid  compounds  of  carbon  have  an  intricate 
molecular  architecture,  and  their  structure  is  un- 
stable. These  compounds  of  carbon,  nitrogen, 
hydrogen  and  oxygen,  with  sulphur  or  phosphorus, 
alone  possess  the  specific  fluidity  and  exhibit  the 
phenomena  of  movement  which  are  characteristic 
of  living  matter.  When  considered  separately  the 
phenomena  of  movement  and  reproduction  are  the 
only  two  characteristics  of  living  matter  which  are 
peculiar  to  the  compounds  of  carbon  and  nitrogen. 
Growth  is  in  a  sense  exhibited  by  other  bodies.  This 


CHARACTERS  OF  LIVING  MATTER        9 

kind  of  growth,  however,  is  not  due  to  assimilation, 
but  to  chemical  affinity  by  which  the  atoms  of 
different  elements  select  or  have  a  preference  for 
the  atoms  of  other  elements,  in  the  way  that  one 
atom  of  nitrogen  is  capable  of  combining  with  three 
atoms  of  chlorine  and  thereby  forming  a  molecule 
consisting  of  four  atoms.  Side-chains  and  rings  are 
formed  by  materials  which  have  a  similar  affinity  ; 
two  molecules  may  be  united  to  form  a  more  complex 
molecule  ;  by  such  a  process  growth  may  be  said  to 
occur.  In  a  similar  way  change  sometimes  takes 
place  within  a  molecule  by  a  rearrangement  of  the 
atoms  within  it ;  no  loss  or  addition  occurs  in  such 
an  arrangement ;  the  same  number  of  atoms  of  the 
same  element  exist  in  the  molecule,  but  their  position 
is  changed,  as  when  ammonium  cyanate  becomes 
converted  into  urea. 

CH4N20=CH4N20  i.e.  CN'ONH4  becomes  CONH2'NH2. 

Ammonium  Urea 

cyanate 

The  Atomic  doctrine  of  Democritus  was  accepted 
wholly  or  in  part  by  most  of  the  philosophers  of  the 
Renaissance  and  their  successors  until  Dalton  formu- 
lated his  law  of  multiple  proportions,  which  conferred 
upon  the  theory  of  atoms  a  new  significance.  This 
doctrine  still  stands  firm,  although  there  have  been 
notable  secessions  from  it ;  without  this  fundamental 
conception  of  matter,  a  theory  of  the  material  universe 
is  almost  impossible.  The  idea  of  gravitation  and 
the  polarity  of  magnetism  has  induced  in  the  minds 
of  some  ardent  thinkers  and  observers  "  the  concep- 
tion that  atoms  and  molecules  are  endowed  with 
attractive  and  repellent  poles,  by  the  play  of  which 


10  THE  THEORY  OF  IONS 

definite  forms  of  crystalline  architecture  are  produced. 
Thus  molecular  force  becomes  structural.  It  re- 
quired no  great  boldness  of  thought  to  extend  its 
play  into  organic  nature,  and  to  recognise  in  mole- 
cular force  the  agency  by  which  both  plants  and 
animals  are  built  up." 

It  may  be  considered  proved  that  all  the  energy 
of  this  earth  is  derived  from  the  sun.  Growth  and 
reproduction  have,  however,  been  supposed  to  be 
the  production  of  a  special  kind  of  energy  called 
vital  force,  under  the  influence  of  which  plants  and 
animals  exhibit  the  special  manifestations  of  a 
living  organism.  But  within  the  last  generation 
our  ideas  of  the  vital  processes  have  become  con- 
siderably changed,  and  few  observers  at  the  present 
day  would  argue  that  all  the  phenomena  observed 
in  an  organism  are  the  result  of  a  single  kind  of 
energy  or  force.  Indeed,  from  our  knowledge  of  the 
transformation  of  energy,  the  phenomena  of  vitality 
may  be  considered  to  be  due  to  a  combination  of 
forces  acting  in  harmony  ;  and,  as  we  travel  back- 
ward in  our  analysis,  we  arrive  at  the  conclusion 
that  the  sun  is  the  physical  source  of  that  exhibition 
of  force  which  we  call  life.  The  matter  in  living 
organisms  is  the  same  as  the  matter  of  inorganic 
substances.  No  substance  in  an  animal  or  vegetable 
differs  from  the  same  substance  in  the  earth,  air  or 
water.  Every  portion  of  an  organic  being  can  be 
reduced  to  purely  inorganic  matter.  Is  the  force 
which  is  required  to  form  organic  substance  in  an 
animal  body  different  from  the  force  or  forces 
required  to  form  the  same  substances  outside  the 
organism  ?  True  it  is  that  certain  protein  sub- 


CHARACTERS  OF  LIVING  MATTER       11 

stances  still  baffle  the  skill  of  the  synthetic  chemist ; 
but  it  is  the  compounding  of  forces  belonging  equally 
to  the  organic  and  the  inorganic  world  which  brings 
about  the  evidences  of  vitality.  True  it  is  that  the 
question  of  identity  remains  unsolved.  The  body 
wastes  and  it  is  renewed  ;  but  the  identity  remains 
the  same  ;  and,  with  a  Master  in  Science  who  gave 
much  time  to  the  consideration  of  this  subject,  we 
may  say,  "  The  matter  of  any  period  may  be  all 
changed,  while  consciousness  exhibits  no  solution 
of  continuity.  Like  changing  sentinels  the  oxygen, 
hydrogen,  and  carbon  that  depart  seem  to  whisper 
their  secret  to  their  comrades  that  arrive,  and  thus, 
while  the  Non-Ego  shifts,  the  Ego  remains  the  same. 
Constancy  of  form  in  the  grouping  of  the  molecules, 
and  not  constancy  of  the  molecules  themselves,  is 
the  correlative  of  this  constancy  of  perception. 
Life  is  a  wave  which  in  no  two  consecutive  moments 
of  its  existence  is  composed  of  the  same  particles." 


II.— THE  IONS 

THE  dissociation  of  combined  elements,  and  the 
formation  of  ions  or  unattached  atoms,  and  meres* 
of  substances,  having  an  electrical  reaction,  is  brought 
about  by  various  influences,  the  best  known  of  which 
are  heat,  light,  chemical  action,  electricity,  Rontgen 
and  other  rays.  Almost  all  dilute  solutions  contain 
ions  derived  from  the  substance  in  the  solution  ; 
and  gases  contain  some  of  their  elements  in  the  same 
condition.  The  dissociation  of  combined  elements 
under  various  circumstances  has  long  been  known 
to  scientists  ;  and,  in  recent  years,  the  theory  of 
ions  has  been  used  to  explain  various  phenomena, 
such  as  electrolysis.  When  a  strip  of  pure  zinc  and 
a  strip  of  platinum  are  dipped  in  acidulated  water 
neither  metal  will  be  affected  so  long  as  they  are 
unconnected.  But  if  they  are  connected  by  a  wire, 
a  chemical  action  takes  place  between  the  zinc  and 
acid  (e.g.  H2S04),  oxygen  and  hydrogen  are  dis- 
engaged and  an  electric  current  passes  along  the 
wire.  The  gases  are  disengaged  at  the  electrodes, 
but  not  indiscriminately.!  The  dissociated  gases 

*  Merus,  a,  urn:  real,  pure,  genuine;  alone,  nothing  else, 
without  mixture  ;  that  with  which  nothing  is  united. 

t  It  is  well  known  that  this  is  not  a  simple  and  direct 
chemical  action,  but  is  a  double  action,  which  may  be  repre- 
sented by  the  following  equations  : 

At  the  Cathode.  At  the  Anode. 

2H2S04=2H2+2S04    and 

12 


THEIR  FORMATION  13 

are  charged  with  electricity  and  are  called  ions  ; 
they  travel  through  the  water  to  the  electrodes 
where  they  discharge  their  electricity  ;  the  hydrogen 
conveying  positive  electricity  to  the  cathode,  and 
the  oxygen  conveying  negative  electricity  to  the 
anode,  where  they  escape.  Many  substances  may 
be  dissociated  into  ions  by  electricity,  e.g.  hydro- 
chloric acid,  ammonia,  carbonic  acid,  acetylene, 
and  ozone  is  formed  from  oxygen  of  the  air,  ions  being 
formed  in  each  case. 

All  substances  cannot  be  ionised,  nor  are  all 
substances  conductors  of  electricity.  If  the  two 
poles  of  a  Battery  are  connected  by  a  bar  of  graphite 
the  current  readily  passes  ;  but  if  they  are  connected 
by  sulphur  no  current  will  pass.  Conductors  of 
electricity  are  of  two  kinds  ;  those  which  become 
heated,  including  all  metals  and  some  non-metals, 
and  those  which  undergo  a  chemical  change  during 
conduction.  The  latter  include  a  very  large  number 
of  compound  substances  in  a  liquid  state  or  in  some 
solvent.  Pure  water  is  a  non-conductor,,  and  when 
the  poles  of  a  battery  are  inserted  into  it  no  current 
passes  ;  but  if  some  hydrochloric  or  other  acid  is 
added  the  solution  becomes  a  conductor  and  a  cur- 
rent passes  ;  at  the  same  time  hydrogen  and  chlorine 
are  disengaged  at  the  cathode  and  anode  respectively, 
i.e.  the  acid  becomes  dissociated  into  ions  charged 
with  electricity  which  they  convey  to  the  electrodes 
— they  are  electrolysed  and  the  liquid  is  called  an 
electrolyte.  It  is  the  substance  in  the  liquid  which 
is  really  the  electrolyte  and  which  becomes  ionised  ; 
it  is  usually  understood  to  be  in  solution  in  water. 
Liquids  are  classified  as  follows  :*  Non-electrolytes 

*  Newth's  "  Inorganic  Chemistry,"  tenth  edition,  p.  97. 


14  THE  THEORY  OF  IONS 

are  liquids  which  do  not  conduct  electricity  or  only 
do  so  with  difficulty  because  they  do  not  become 
ionised ;  e.g.  pure  water,  aqueous  solutions  of 
alcohol  or  sugar,  benzene,  and  a  large  number  of 
organic  compounds  which  do  not  fall  under  the  head 
of  salts,  acids  or  bases..  Electrolytes  are  readily 
ionised  and  good  conductors  of  electricity,  e.g. 
aqueous  solution  of  chloride  of  sodium  or  of  strong 
acids,  strong  bases  and  nearly  all  salts.  There  are 
materials  which  stand  between  the  two  called  Half- 
electrolytes,  including  weak  acids,  e.g.  tartaric, 
acetic  and  oxalic  acids ;  the  weak  bases,  e.g. 
ammonium  hydroxide,  and  hydroxides^  of  metals 
other  than  alkaline  earths. 

Dissociation    takes    place    in    chemicals    having 

(a)  a  homogeneous  system,  like  ammonium  chloride, 
ammonium    sulphide,    mercurous    chloride,    phos- 
phorous  pentachloride  or  amylene    chloride  ;    and 

(b)  in  systems  that  are  not  homogeneous,  as  the 
hydrated  salts,  the  carbonates  of    lime,  magnesia 
and  silver,  the  oxides  of  mercury  and  iridium,  com- 
pounds of  the  metallic  oxides  and  metallic  hydrides.* 
Ions  are  produced  in  many  ways,  both  in  liquids  and 
gases.     When  a  gas  is  traversed  by  uranium  rays 
ions  are  produced  which  are  charged  with  electricity, 
and  the  same  effect  follows  the  action  of  cathode 
rays.f    The  ionisation  is  independent  of  the  com- 
position of  the  gas,  and  varies  directly  as  the  pressure 
and  density.} 

Some  salts  are  more  or  less  decomposed  by  water, 

*  Watts'  "Diet.  Chern.  ":  article,  "Dissociation." 
I  McLennan:  Proc.  Roy.  Soc.,  1900,  Ixvi.,  375. 
Ibid. 


THEIR  FORMATION  15 

ions  being  formed.  Salts  of  a  strong  acid  and  a  weak 
base  are  so  decomposed,  and  the  solution  contains 
a  free  acid  and  a  residual  salt,  which  may  be  a  basic 
or  a  normal  salt.  Mercuric  sulphate  is  so  decom- 
posed.* 

Dissociation  takes  place  in  colloidal  solutions  just 
as  it  does  in  watery  solutions.  Levif  has  shown  that 
potassium  iodide  is  dissociated  to  the  same  extent 
in  solution  of  gelatine,  agar-agar  or  silicic  acid,  as 
in  aqueous  solution.  Dissociation  also  occurs  in 
the  salts  of  the  blood,  lymph,  serum,  and  other 
animal  or  vegetable  fluids.  Dissociation  is  produced 
by  heat  and  in  some  bodies  by  a  low  temperature. 
Nitrogen  tetroxide  may  become  completely  disso- 
ciated at  27°  C.  Regnault  showed  by  experiment 
that  some  bodies  which  are  decomposed  by  heat  into 
one  or  more  solid  bodies  and  a  gas,  give  off  the  gas 
more  freely  when  in  the  presence  of  a  foreign  gas 
than  when  exposed  to  the  products  of  their  own 
decomposition.  Chalk  loses  its  C02  more  freely  in 
air  than  in  an  atmosphere  of  C02 ;  and  hydrated 
salts  give  off  their  water  of  hydration  more  freely 
in  an  atmosphere  of  dry  air  than  in  one  of  watery 
vapour.  Similarly,  venous  blood  gives  up  C02  more 
freely  in  pure  air  than  in  an  atmosphere  containing 
much  C02,  according  to  the  laws  of  diffusion. 

The  formation  of  ions  depends  somewhat  upon  the 
constitution  of  the  molecules,  for  many  substances 
which  consist  mainly  of  polymerised  molecules  do 
not  readily  become  ionised.  In  order  that  a  sub- 
stance shall  possess  electrolytic  conductivity  its 

*  Guinchant :  Bull,  de  Soc.  Chim.,  1896,  iii.,  555. 
f  Gazetta,  1900,  ii.,  64-70. 


16  THE  THEORY  OF  IONS 

chemical  constitution  must  be  such  that  ions  can 
be  formed  from  it,  its  dielectric  constant  must  be 
high,  and  it  should  not  contain  a  large  proportion 
of  polymerised  molecules.*  It  is  also  extremely 
probable  that  the  degree  of  dissociation  depends 
considerably  upon  the  capacity  of  the  ions  to  unite 
with  molecules  of  the  sol  vent,  f  Many  substances 
with  large  dielectric  constants,  e.g.  water,  formic 
acid,  methyl  alcohol  and  ethylalcohol,  are  bad 
conductors  of  electricity  because  they  consist  largely 
of  polymerised  molecules.}  Other  substances  with 
large  dielectric  constants  and  small  polymerisation 
are  unsuitably  constituted  for  electrolytic  conduc- 
tivity, thus  :  nitrobenzine,  ethyl  nitrate,  and  benzo- 
nitrate  contain  the  groups  N02,  N03  and  CN, 
which  readily  form  ions,  but  they  also  contain  the 
groups  C6H5  and  C2H5,  which  have  never  been  ob- 
served in  ions.§ 

The  explanation  of  dissociation  or  the  formation 
of  ions  is  not  yet  complete.  Pflaunder  and  Lemoine 
explained  it  by  the  theory  of  the  Action  of  Mass, 
Thompson  by  the  Vortex  Atom  hypothesis,  and 
others  explain  it  by  the  kinetic  theory  of  gases  and 
the  principles  of  thermo-dynamics  ;  but  no  explana- 
tion up  to  the  present  time  has  been  found  satis- 
factory to  all  parties. 

The  ions  are  anodic  or  cathodic,  that  is  they  are 
charged  with  positive  or  negative  electricity.  But 
their  electrical  reaction  may  change  or  is  convertible, 
and  the  conversion  is  demonstrable  by  experiment.  || 

*  Abegg  :  Zeit.fur  Electro-Chem.,  1899,  v.,  353. 
t  Ibid.  J  Ibid.  §  Ibid. 

|j  Kiister:  Zeit.fur  Electro-Chew,.,  1897,  iv.,  105. 


IONS  CONDUCT  ELECTRICITY  17 

The  ions  which  convey  positive  electricity  or  are 
positively  electrified  travel  to  the  cathode  or  negative 
electrode  during  electrolysis,  and  are  cations  or 
positive  ions ;  they  include  hydrogen  and  the 
metals.  Ions  which  convey  negative  electricity 
travel  to  the  anode  or  positive  electrode,  and  are 
called  anions  ;  they  include  most  of  the  metalloids 
and  non-metals.  Cations  consist  for  the  most  part 
of  a  single  element,  e.g.  Na,  H,  K,  Li,  Pb,  Cu,  Fe 
or  Bi.  But  many  anions  are  compounds  of  two 
or  more  elements,  e.g.  OH,  N03,  C103,  C2H302, 

so3,  CA,  po4. 

All  ions  do  not  convey  an  equal  amount  of 
electricity,  but  their  capacity  varies  with  the  valency 
of  the  atoms.  A  unit  has  been  established  whereby 
this  capacity  may  be  measured ;  the  ions  of 
1  gramme-molecule  of  hydrogen  will  convey  an 
amount  of  electricity  which  is  equivalent  to  96,550 
coulombs  ;  and  the  ions  of  all  monovalent  elements 
carry  an  equal  amount  of  electricity,  the  ions 
of  divalent  elements  twice  that  amount,  and  so  on. 
The  molecular  conductivity  of  any  liquid,  however, 
depends  upon  the  degree  of  dissociation,  for  it  is 
the  ions  alone  in  any  solution  which  convey  elec- 
tricity, the  undissociated  molecules  being  inoperative. 
The  molecular  conductivity  is  increased  up  to  a 
certain  point  by  dilution  of  the  liquid,  which  is  due 
partly  to  the  greater  rapidity  of  migration  of  the 
ions  and  partly  to  the  formation  of  a  greater  number 
of  ions  in  the  solution.  The  more  a  fluid  is  diluted 
so  much  the  greater  is  the  ionisation  and  rate  of 
molecular  conductivity  up  to  a  certain  point ;  when 
this  point  is  reached  there  is  no  further  increase  in 

2 


18  THE  THEORY  OF  IONS 

the  ionic  velocity  or  conductivity,  for  it  has  been 
shown  that  henceforth  the  ionic  velocity  decreases 
with  the  dilution.*  Even  when  the  conditions  are 
the  same,  ions  travel  at  different  rates  ;  but  given 
the  same  concentration  and  electrical  conditions  all 
ions  of  one  kind  travel  with  a  constant  velocity,  f 
Thus,  the  cation  H*  travels  with  a  velocity  which 
is  twice  as  great  as  the  anion  OH',  and  five  times  as 
great  as  that  of  the  cation  K\  The  ionic  velocity 
is  determined  by  conductivity  experiments,  and  it 
is  found  to  vary  with  the  condition  ;  by  this  method 
the  velocity  of  ions  produced  by  X  rays  in  air,  0, 
C02  and  H,  has  been  determined.  J  It  is  even  in- 
fluenced by  the  solvent,  e.g.  the  ionic  velocity  ot 
CF  in  aqueous  solution  and  in  glycerol  solution 
was  found  by  Cattaneo§  to  be  for  sodium  chloride 
0-658  and  0-645  respectively,  and  for  ammonium 
chloride  0-510  and  0-568  respectively.  Moisture  also 
diminishes  the  velocity  of  ions,  especially  negative 
ions  ;  and,  in  general,  the  velocity  of  negative  ions 
is  greater  than  that  of  positive  ions.|| 

The  degree  of  dissociation  or  ionisation  of  salts 
in  solution  is  usually  determined  by  conductivity 
experiments  at  a  temperature  of  18  to  25°.  The 
temperature  has  considerable  influence  upon  the 
formation  of  ions.  Dampier  and  Williams ^  have 
shown  that  the  degree  of  dissociation  at  18  to  25° 
is  not  comparable  with  that  at  freezing-point.  They 
also  showed  that  the  degree  of  dissociation  at  0° 

*  Hans  Jahn  :  Zeit.  fur  Physik.-Chem.,  1900,  xxxv.,  1-10. 

f  Hittorf  :  cf.  Newth's  "Inorganic  Chemistry." 

J  Zeleny  :  Proc.  Roy.  Soc.,  1900,  Ixvi.,  238-241. 

§  Real  Acad.-Linc.,  1896,  v.  and  vi. 

|j  Zeleny  :  loc.  cit.          IT  Proc.  Roy.  Soe.,  1900,  Ixvi.,  192. 


IONS  CONDUCT  ELECTRICITY  19 

varies  with  the  concentration  of  the  solution,  and 
that  at  0°  the  dissociation  falls  less  rapidly  with 
increasing  concentration  than  at  a  higher  tempera- 
ture. 

The  electro-motive  force  (E.M.F.) required  to  separ- 
ate the  ions  from  their  electrical  charges  varies,  which 
Hans  Jahn  considers  is  probably  a  cause  of  apparent 
divergences  from  Ostwald's  law.*  As  the  ratio  of 
ionic  concentration  can  be  found  by  E.M.F.  observa- 
tions, so  likewise,  assuming  Ostwald's  law,  can  the 
actual  concentration  be  determined.  The  ionic 
concentration  of  a  dilute  solution  of  potassium 
chloride  was  calculated  from  E.M.F.  observations  and 
compared  with  that  of  six  other  solutions  of  varied 
strength,  and  the  value  of  these  was  found  to  vary 
from  0-001638  to  0-001642.  Similar  calculations 
were  made  from  solutions  of  sodium  chloride  and 
hydrochloric  acid.  By  assuming  the  value  of  the 
most  dilute  solution,  Hans  Jahn  calculated  from  it 
the  ionic  concentration  of  the  stronger  solutions, 
and  he  found  these  values  agreed  with  those  ob- 
tained by  the  dilution  law. 

The  presence  of  ions  in  a  solution  influences  the 
osmotic  pressure.  All  substances  in  solution  behave 
like  gases,  the  dissolved  molecules  exerting  pressure 
on  the  sides  of  the  containing  vessel  in  their  effort 
to  diffuse  through  space.  But  the  osmotic  pressure 
depends  upon  whether  the  substance  in  solution  is 
an  electrolyte  or  a  non-electrolyte.  The  osmotic 
pressure  of  non-electrolytes  in  solution  is  propro- 
tionate  to  the  number  of  contained  molecules  ;  but 
in  the  case  of  electrolytes  the  pressure  is  in  propro- 

*  Loc.  cit. 

2—2 


20  THE  THEORY  OF  IONS 

tion  to  the  molecules  +  ions  in  the  solution.  Sugar 
is  a  non-electrolyte,  and  0-5  per  cent,  solution  exerts 
exactly  half  the  pressure  of  a  1  per  cent,  solution. 
But  NaCl  is  an  electrolyte,  and  a  0-5  per  cent, 
solution  exerts  more  than  half  the  pressure  of  a 
1  per  cent,  solution,  because  the  dissociation  is 
greater  and  there  are  relatively  more  ions  in  the 
weaker  than  in  the  stronger  solution. 
'  During  diffusion,  it  is  found  that  the  presence  of 
a  dividing  medium  or  septum  influences  the  rate  of 
diffusion  and  the  velocity  of  the  ions.  The  rate  of 
diffusion  of  various  gases  through  porous  septa  is 
nearly  inversely  proportional  to  the  square  root  of  the 
density  of  the  gases  ;  thus  H  passes  through  porous 
septa  four  times  as  quickly  as  0,  and  nearly  three 
times  as  quickly  as  steam.  *  Many  experiments  have 
been  performed  which  show  that  septa  influence 
the  velocity  of  the  transmission  of  ions.  The  re- 
lative velocity  of  cations  is  in  all  cases  less  when  a 
dividing  membrane  is  used  than  when  no  mem- 
brane is  used  ;  but  the  difference  is  greatest  when 
the  septum  consists  of  an  animal  membrane,  and  is 
smaller  or  comparatively  negligible  when  the 
septum  consists  of  parchment  paper  or  porous  clay.f 
Bein  determined  the  rate  of  transmission  of  ions 
through  clay,  parchment  paper,  gold-beater's  skin, 
and  fish-bladder  of  H,  Na,  Li,  Ca,  and  Cd  in  the 
form  of  chlorides,  and  in  every  instance  the  rate  of 
transmission  of  cations  through  gold-beater's  skin 
and  fish-bladder  was  diminished.  J  Absorption 

*  Watts'  "  Diet.  Chem." 

t  Bein :  Zeit.  Physikal-Chem.,  1899,  xxviii.,  439. 
LOG.  cit. 


EFFECT  ON  ORGANIC  FUNCTIONS       21 

through  animal  membranes  has  also  been  studied 
from  the  ionic  standpoint  by  Rudolf  Hober.*  He 
has  shown  that  the  salts  absorbed  from  the  small 
intestine  into  the  blood  are  hypertonic,  isotonic,  and 
hypotonic  ;  and  that  isotonic  salts  are  absorbed  at 
different  rates.  He  used  solutions  so  dilute  that  the 
salts  were  almost  completely  dissociated  electro- 
lytically,  and  he  found  that  they  behaved  differently 
according  to  the  proportion  of  the  contained  ions 
or  the  ionic  concentration.  The  cations  K,  Na,  and 
Li,  were  absorbed  with  almost  equal  rapidity ;  NH4 
and  urea  more  quickly  ;  Ca  more  slowly,  and  Mg 
slowest  of  all.  Of  the  anions,  Cl  was  absorbed  most 
rapidly,  then  followed  in  order  Br,  I,  N03  and  S04. 
The  absorption  of  Ba  could  not  be  observed  because 
of  its  injurious  action  on  the  mucous  membrane. 

Various  other  biological  functions  have  also  been 
considered  from  the  standpoint  of  the  ionic  theory, 
For  instance,  chloride  of  sodium  is  a  common  and 
almost  essential  constituent  of  ordinary  human 
food,  and  it  has  been  asserted  that  its  presence  in 
food  provokes  or  aids  the  secretion  of  hydrochloric 
acid  in  the  stomach.  Now,  it  is  not  proved  that 
the  stomach  is  impermeable  to  CF  ions  ;  but  Beurath 
and  Sachs f  consider  they  have  proved  that  the  acid 
secretion  has  no  relation  to  the  presence  or  absence 
of  chloride  of  sodium  in  the  food  ;  that  the  absence 
of  Cl  ions  from  the  food  does  not  prevent  the  forma- 
tion of  HC1  in  the  stomach  ;  nor  does  the  introduc- 
tion of  a  chlorine-free  solution  into  the  stomach 
abolish  the  secretion,  which  comes  from  the  blood. 

*  Pfliiger's  Archiv,  1898,  Ixx.,  624. 
t  Ibid.,  1905.,  cix.,  466. 


22  THE  THEORY  OP  IONS 

The  taste  or  flavour  of  substances  is  due  to  the 
reaction  which  is  produced  by  a  solution  of  that 
substance  upon  the  nerve-endings  ;  and  the  sense 
of  taste  is  regarded  by  some  authorities  as  being 
due  to  the  dissociation  which  takes  place  in  the 
solution,  that  is,  to  the  action  of  ions  upon  the 
surface  of  the  tongue  or  the  nerve-endings.  Eichards* 
attributes  the  sour  taste  of  acids  to  the  action  of 
H  ions  in  the  solution  ;  which  view  he  considers 
upheld  by  the  fact  that  a  solution  of  HC1  of  dis- 
tinctly acid  taste  becomes  tasteless  when  neutralised 
by  potash.  Dilutions  of  less  ionised  acids,  e.g. 
acetic  and  tartaric,  are  not  so  sour  to  the  taste  as 
corresponding  solutions  of  mineral  acids.  When  a 
small  quantity  of  sodium  acetate  is  added  to  a  dilute 
solution  of  HC1  or  acetic  acid  the  sour  taste  is 
diminished,  which  is  in  accordance  with  the  view 
that  almost  wholly  dissociated  sodium  acetate  is 
capable  of  destroying  the  freedom  of  H  ions. 
Kalenberg,t  on  the  other  hand,  says  that  the  sour 
taste  of  acids  and  acid  sodium  salts  is  obtained  at 
concentrations  of  H  ions  below  the  limit  for  acids  ; 
hence  the  sour  taste  of  acid  sodium  salts  cannot  be 
attributed  to  the  H  ions  which  are  present,  but 
rather  that  it  is  due  to  the  acid  ion  ;  and  he  considers 
this  to  militate  against  the  view  which  explains 
the  sense' of  taste  by  the  theory  of  ions.  Hober  and 
Kiessonf"  also  appear  to  consider  the  dissociation 
theory  to  afford  an  unsatisfactory  explanation  of 
the  sense  of  taste.  Richards, §  however,  says  that 

*  Amer.  Jour.  Chem.,  1898,  xx.,  121-126. 
t  Jour.  Physiol.  Chem.,  1900,  iv.,  33-37. 
J  Abstracts,  Jour.  Chem.  Soc.,  1899,  i.,  206. 
§  Jour.  Physiol.  Chem.,  1900,  iv.,  207-211. 


EFFECT  ON  ORGANIC  FUNCTIONS       23 

the  sour  taste  of  acid  salts  is  stronger  than  would  be 
expected  from  the  concentration  of  H  ions,  but  he 
does  not  consider  that  this  militates  against  an 
explanation  of  taste  from  the  ionic  standpoint.  If 
the  taste  is  due  to  a  chemical  action  upon  a  substance 
on  the  surface  of  the  tongue,  the  sensation  may  be 
accompanied  by  the  removal  of  H  ions,  and  further 
dissociation  would  then  occur  in  accordance  with 
mass-action  law.  Although  the  degree  of  dissociation 
in  a  liquid  is  correctly  ascertained  no  quantitative 
connexion  could  be  obtained  from  the  taste.  This 
explanation  is  also  in  agreement  with  paralysis  of 
the  sense  of  taste  which  follows  the  application  of 
concentrated  solutions  to  the  tongue.  H-  and  OH7 
ions  are  those  which  possess  the  most  marked  taste, 
and  are  those  most  likely  to  cause  reactions  in  the 
substance  of  the  tongue,  and  such  phenomena  are 
not  opposed  to  an  explanation  of  taste  by  the  ionic 
theory. 

The  effects  of  dissociated  substances  upon  many 
organisms  have  been  observed.  Acid  ions,  even 
C02,  stop  the  contractile  manifestations  of  proto- 
plasm ;  the  ions  of  alkalies  at  first  increase  its 
activity.  W.  E.  Garrey*  states  that  the  effect  of 
such  chemicals  upon  flagellated  infusoria  is  analogous 
to  that  of  heat,  light,  galvanism,  and  other  stimuli. 
Inorganic  acids  have  equal  effects  upon  them,  if 
their  ionic  concentration  is  the  same  ;  but  organic 
acids  behave  differently  and  their  effect  is  greater 
than  would  be  expected.  When  fungi  are  subjected 
to  the  action  of  deleterious  ions  they  offer  in  general 
more  resistance  than  higher  organisms.  Clarke  f 

*  Amer.  Jour.  Physiol,  1900,  iii.,  291-315. 
t  Jour.  Physiol.  Chem.,  1899,  iii.,  263. 


24  THE  THEORY  OF  IONS 

found  that  the  anion  OH  is  rather  more  toxic  to 
moulds  than  the  cation  H  ;  and  the  toxicity  of  the 
anions  Cl,  Br  and  I,  increases  slightly  with  their 
atomic  weight.  The  ion  of  cyanogen  radical  is 
powerfully  poisonous  to  fungi,  and  potassium 
cyanide  has  nine  times  more  toxicity  than  that  of 
HC1.  Mercuric  chloride  and  silver  nitrate  are  about 
equally  toxic  to  moulds,  and  are  followed  closely 
by  potassium  dichromate,  potassium  chromate,  and 
formaldehyde.  In  many  cases  the  dissociation 
lessens  the  toxic  effects.  Out  of  eight  acids,  six 
were  more  toxic  in  the  molecular  than  in  the  ionised 
form.  The  anions  of  mineral  acids  have  a  low  toxic 
value  for  fungi  :  those  of  HC1,  HN03,  and  H2S04 
have  a  toxicity  of  less  than  -^  that  of  H  ions.  The 
undissociated  HCN  molecule  has  a  toxicity  76-6 
times  that  of  H  ions  ;  that  of  acetic  acid  2-8  times 
that  of  H  ions  ;  but  when  the  hydrogen  in  acetic 
acid  is  replaced  by  chlorine  the  toxicity  increases, 
but  the  dissociation  increases  also  and  the  two 
effects  partially  balance  one  another.* 

Chloride  of  sodium  is  toxic  to  many  low-formed 
organisms,  and  to  contractile  tissues  generally. 
Thus,  fundulus  ova  will  develop  in  distilled  water, 
but  not  in  water  which  only  contains  sodium 
chloride  ;  if,  however,  some  calcium  chloride  also 
be  added  to  the  water  the  development  proceeds 
normally  ;  from  which  it  is  inferred  that  sodium  ions 
are  toxic,  but  calcium  ions  anti  toxic,  f  Strontium 
ions  have  the  same  antitoxic  effect  as  calcium  ions. 

What   influence   has   ionisation    upon    muscular 

*  Clarke :  loc.  cit. 

t  Osborne :  Proc.  Physiol.  Soc.,  1905,  x.-xii. 


IONS  AND  MUSCULAR  ACTIVITY       25 

contractility  ?  There  is  abundant  evidence  of 
the  splitting  up  of  muscle  constituents  during 
activity,  and  some  evidence  of  their  ionisation. 
Living  resting  muscle  has  a  neutral  or  alkaline 
reaction  ;  but  during  activity  the  reaction  becomes 
acid  from  the  development  of  sarcolactic  and 
carbonic  acids  which  result  from  the  splitting  up  of 
a  more  complex  substance  or  substances  about  the 
time  of  contraction.  We  do  not  know  exactly  what 
occurs  during  contraction.  "  It  may  be  that  the 
chemical  changes  at  the  bottom  of  the  contraction 
do  not  involve  the  real  living  material  of  the  fibre, 
but  some  substance  manufactured  by  the  living 
material.  It  may  be  that  when  a  fibre  contracts 
it  is  this  substance  which  explodes  and  not  the  fibre 
itself.  It  may  be  a  compound  of  carbon  and 
hydrogen  which  explodes,  the  products  being  sarco- 
lactic and  carbonic  acids,  but  such  is  not  yet 
proved."*  When  a  muscle-nerve  preparation  is 
subjected  to  a  shock  from  an  induction  coil  a  change 
passes  along  the  nerve  to  the  end-plate,  where  it  is 
transmuted  into  a  muscle  impulse.  This  takes 
place  in  the  latent  period.  It  is  evident  that  the 
electricity,  whatever  change  it  undergoes  in  its 
course  through  the  nerves,  sets  up  an  electrolytic 
process  or  an  "  explosive  decomposition  which  leads 
to  the  formation  of  sarcolactic  acid  and  disengage- 
ment of  C02  and  heat,  accompanied  by  a  visible 
wave  of  contraction  in  the  muscle  itself,  "f  The 
proportion  of  the  products  bears  a  constant  rela- 
tionship to  the  energy  and  duration  of  the  con- 
traction, or  vice  versa,  the  energy  of  the  contraction 

*  Foster's  "Physiology,"  vol.  i.,  p.  106.         f  Ibi^  P-  125- 


26  THE  THEORY  OF  IONS 

bears  a  constant  relationship  to  the  consumption 
of  an  explosive  material  which  results  in  the 
development  of  C02  and  sarcolactic  acid.  The 
nature  of  this  chemical  change  is  not  clearly  under- 
stood ;  but  we  know  that  the  materials  essential  for 
the  process  must  contain  carbon  and  hydrogen,  and 
we  also  know  that  oxygen  is  certainly  consumed  in 
the  form  of  0'  or  OH'.  The  H-  ion  may  also  be  in 
use  ;  and  sarcolactic  acid  is  probably  formed  by  the 
union  of  acid  or  OH7  ions  with  products  of  decom- 
position of  the  exploded  molecule  as  a  secondary 
reaction.  Muscle  substance  could  not  exist  without 
water  ;  and  the  explosive  substance  may  be  in  solu- 
tion in  the  water.  Now  ions  alone  can  take  part 
in  the  conduction  of  the  electric  current  through 
liquids  or  gases  ;  the  undissociated  molecules  being 
inoperative,  ergo  ions  convey  the  electricity  through 
the  muscle  fibre.  The  ions  only  remain  active  and 
have  an  independent  existence  so  long  as  they 
retain  their  electrical  charges,  which  may  be  enor- 
mous. A  great  amount  of  energy  is  transformed 
into  heat  during  muscular  activity,  and  although  we 
cannot  tell  what  is  the  exact  chemical  action  which 
takes  place  we  may  judge  of  its  importance  by 
analogy  ;  e.g.  when  a  known  combination  of  carbon 
and  hydrogen,  such  as  methane,  undergoes  oxidation 
much  energy  is  liberated  in  the  form  of  heat,  as  shown 
by  the  following  thermo-chemical  equation  : 

CH4  +  202  =  C02  +  2H20  +212,000  calories. 

Which  means  that  when  1 6  grammes  of  methane  are 
combined  with  64  grammes  of  oxygen  there  are 
produced  44  grammes  of  carbon  dioxide,  36  grammes 


HEAT  DUE  TO  IONTSATION  27 

of  water,  and  212,000  calories  or  units  of  heat ;  in 
other  words,  the  energy  of  16  grammes  of  methane 
and  64  grammes  of  oxygen  together  is  more  than 
that  possessed  by  44  grammes  of  carbon  dioxide 
and  36  grammes  of  water  by  an  amount  which  would 
produce  212,000  calories.  During  muscular  action 
a  similar  amount  of  force  over  and  above  that 
which  is  necessary  to  produce  sarcolactic  acid  and 
carbon  dioxide  produces  the  contraction  and  is 
transformed  into  heat. 

The  effects  of  ions  on  contractile  tissues  have  been 
observed,  and  Loeb  asserts  that  sodium  chloride  is 
a  poison  to  them  all.  The  well-known  effects  of 
ions  on  muscular  tissue  are  masked  by  the  presence 
therein  of  organic  substances  having  large  molecules, 
which  is  regarded  as  an  indication  of  their  com- 
bination.* Although  the  ions  of  sodium  and 
lithium  are  very  similar  physically,  their  physio- 
logical effects  are  not  equivalent.  There  is  no 
foreign  element  so  slow  to  make  a  noteworthy 
change  in  skeletal  muscle  as  lithium  ;  but  when 
most  of  the  normal  sodium  in  it  has  been  replaced 
by  lithium,  it  is  followed  by  a  characteristic  fall  in 
the  muscular  irritability,  f  A  controversy  has 
existed  for  some  time  as  to  whether  the  action  of 
contractile  tissue  is  of  muscular  or  nervous  origin. 
The  constitution  of  the  environment,  as  well  as  that 
of  the  tissues,  enters  into  the  question  ;  and  many  of 
the  arguments  about  it  have  been  based  upon  the 
ionic  theory.  Loeb  J  experimented  with  the  medusa  ; 

*  Stiles  and  Beer:  Amer.  Jour.  Physiol,  1905,  xiv.,  133. 
t  Millikin  and  Stiles  :  Ibid.,  p.  359. 
J  Ibid.,  1900,  iii.,  383-393. 


28  THE  THEORY  OF  IONS 

and  found  that  in  the  presence  of  calcium  and 
potassium  salts  the  impulses  started  in  the  margin 
and  were  therefore  of  nervous  origin  ;  from  which 
he  concluded  that  the  chemical  rather  than  the 
histological  structure  of  the  ganglia  was  important. 
Howell*  says  the  normal  stimulus  of  contraction 
depends  upon  the  presence  of  calcium  salts,  but  for 
rhythmical  contraction  the  presence  of  potassium 
salts  is  also  necessary.  Loebf  also  considers  that 
calcium,  potassium,  or  sodium  salts  do  not  form 
the  stimulus  for  rhythmical  contraction  in  cardiac 
and  other  contractile  tissues,  but  that  their  presence 
in  the  tissues  in  a  definite  proportion  is  necessary  ; 
if  the  proportion  is  not  correct  a  rhythmical  con- 
traction does  not  take  place.  If  the  amount  of 
sodium  chloride  in  it  is  too  small,  it  may  be  in- 
creased by  placing  the  tissue  in  a  solution  of  pure 
NaCl,  and  a  rhythmic  action  will  then  be  brought 
about ;  if  the  calcium  chloride  is  too  small  increasing 
it  in  the  same  manner  will  initiate  contraction. J 
All  contractile  tissues  do  not  require  the  same 
chemical  constitution  or  environment.  Thus, 
potassium  alone  annihilates  muscular  contraction 
rapidly  ;  but  ciliary  activity,  which  is  considered  to 
be  a  protoplasmic  action  of  the  same  order,  and  cell 
division  will  continue  in  the  presence  of  enormous 
quantities  of  potassium  salts. 

A  similar  discussion  has  arisen  about  the  action 
of  the  heart,  and  has  partly  taken  place  from  the 
standpoint  of  ionic  dissociation.  Attempts,  con- 
sidered by  many  authorities  to  be  successful,  have 

*  Amer.  Jour.  PhysioL,  1898,  ii.,  47. 
t  Loc.  cit.  Loc.  tit. 


INFLUENCE  UPON  CONTRACTILITY     29 

been  made  to  show  that  the  heart  is  automatic,  and 
that  its  action  depends  upon  the  constitution  of  the 
blood.  Ho  well*  says  a  strip  of  vena  cava  from  the 
terrapin's  heart  may  be  kept  in  rhythmic  action  for 
two  or  more  days  if  it  is  immersed  in  a  bath  con- 
taining sodium  chloride  and  calcium  or  potassium 
chloride.  This  renders  very  improbable  the  state- 
ment of  Kronecker  that  cardiac  tissue  only  beats  so 
long  as  serum  albumen  is  supplied  to  it.  It  also 
makes  it  evident  that  the  energy  is  derived  from 
within  the  cardiac  tissue,  and  that  if  the  tissue  is 
supplied  with  an  adequate  stimulus  the  beat  will 
continue  until  the  source  of  the  energy  is  consumed. 
Wilsonf  also  states  that  a  strip  of  muscle  from  the 
apex  of  a  terrapin's  heart  was  kept  alive  by  placing 
it  in  normal  serum  for  several  days  ;  normal  serum, 
however,  did  not  keep  it  in  contraction,  but  a 
regular  rhythmic  contraction  was  induced  by  the 
addition  to  the  serum  of  some  calcium  chloride. 
On  the  other  hand,  LoebJ  concludes  that  the 
presence  of  calcium  and  potassium  chloride  is  not 
essential  for  the  maintenance  of  rhythmic  contrac- 
tion, but  that  their  constant  presence  is  necessary 
indirectly  by  neutralising  the  toxic  effect  of  sodium 
chloride,  which  is  present  in  blood  and  sea-water, 
and  which  he  asserts  is  toxic  to  all  contractile 
tissues. 

*  Loc.  cit.  t  Amer.  Jour.  PhysioL,  1893,  ii.,  82-126. 

J  f finger's  Archiv,  Ixxx.,  229-232. 


III.— IONS  IN  BIOLOGY 

THERE  is  abundance  of  evidence  that  electrical 
changes  are  an  important  item  in  biological  pro- 
cesses, that  chemical  substances  are  built  up  as 
well  as  broken  down  in  living  tissues,  that  living 
substances  are  organised  and  disorganised.  How 
far  the  theory  of  ions  may  account  for  the  changes 
that  take  place  in  living  tissues  and  to  what  extent 
ionisation  is  responsible  for  them  is  at  present 
unknown.  But  that  ionisation  takes  place  in  living 
structures  and  the  presence  of  ions  therein  influences 
biological  processes  is  evident.  On  purely  theoreti- 
cal grounds  Nageli*  considered  that  the  essential 
substance  of  protoplasm,  that  is  the  living  substance, 
must  consist  in  its  ultimate  structure  of  ultra- 
microscopical  solid  particles  or  systems  of  such 
particles  surrounded  by  material  of  a  fluid  con- 
sistence. He  supposed  that  such  particles,  acting 
like  substances  known  as  ferments  or  enzymes, 
produced  chemical  changes  in  the  materials  with 
which  they  are  brought  in  contact,  without  being 
themselves  materially  changed.  McKendrickf  of 
Glasgow  said  in  a  lecture  :  "  When  cells  were  exam- 
ined by  the  highest  microscopical  powers  they  did 
not  seem  to  have  advanced  far  towards  an  explana- 

*  Quain's  "Anatomy,"  vol.  i.,  part  ii.,  "Histology." 
t  Brit.  Med.  Jour.,  1901,  ii.,  817. 
30 


LIFE  31 

tion  of  the  ultimate  phenomena  of  life  ;  and  there 
was  the  same  feeling  when  the  cell  was  attacked 
from  the  chemical  side.  It  would  appear  that  the 
phenomena  of  life  depended  on  changes  occurring  in 
the  interaction  of  particles  of  matter  far  too  small 
to  be  seen  by  the  microscope.  The  physicist  and 
chemist  explained  many  phenomena  by  recourse  to 
the  conception  of  molecules  and  atoms  and  by  the 
dynamical  laws  which  regulated  their  movements. 
The  conception  of  the  existence  of  molecules  in 
living  matter  had  not  escaped  many  physicists. 
Probably  the  germinal  vesicle  of  an  ovum  contained 
millions  of  organic  molecules.  The  conception  of 
physicists  was  that  molecules  were  more  or  less  in 
a  state  of  movement ;  and  the  most  advanced 
thinkers  were  striving  towards  a  kinetic  theory  of 
molecules  and  atoms  which  would  be  as  fruitful  as 
the  kinetic  theory  of  gases.  It  was  conceivable 
that  vital  activities  might  also  be  determined  by 
the  kind  of  motion  that  took  place  in  the  molecules 
of  living  matter.  It  might  be  different  in  kind  from 
that  known  to  physicists.  But  it  was  probable  that 
life  might  be  the  transmission  to  dead  matter,  the 
particles  of  which  already  had  a  special  kind  of 
motion,  of  a  form  of  motion  sui  generis"  The 
process  of  ionisation  appears  to  confer  upon  matter 
a  movement  and  a  power  which  does  not  belong 
to  inert  material ;  for  we  find  that  in  electrical 
conduction  it  is  only  the  ions  which  are  operative, 
and  the  undissociated  molecules  are  inoperative. 

The  protoplasm  of  all  animal  and  vegetable  cells 
is  probably  of  a  similar  constitution.  Water  enters 
largely  into  its  composition.  The  imbibition  of 


32  THE  THEORY  OF  IONS 

water,  up  to  a  certain  point,  accelerates  its  activity  ; 
beyond  this  point  it  is  destructive.  Desiccation 
even  to  a  slight  degree  will  destroy  the  vitality  of 
the  protoplasm  of  all  cells  in  the  higher  animals  or 
plants  ;  but  this  does  not  hold  good  for  certain  low- 
formed  organisms.  We  also  know  that  certain  salts 
are  as  essential  to  protoplasm  as  the  water  which 
acts  as  their  solvent.  But  their  action  shows  that 
an  excess  of  any  chemical  in  a  molecular  form  is 
deleterious  to  protoplasm  ;  and  their  freedom  from 
injury  depends  upon  their  presence  in  the  form  of  a 
dilute  solution.  Plants  absorb  chemical  substances 
through  their  root-hairs  by  osmosis,  each  ingredient 
in  the  moisture  around  the  roots  tending  to  become 
as  abundant  inside  as  outside  the  root-hair.  Absorp- 
tion by  osmosis  only  takes  place  when  the  solution 
outside  is  richer  than  the  cell-sap  in  the  absorbed 
material.  But  in  any  case  the  solution  must  be 
dilute,  because  strong  solutions  would  kill  the 
plant. 

The  evidence  that  salts  are  largely  absorbed  in 
the  form  of  ions  is  increasing.  It  is  also  known  that 
the  proportion  of  ions  in  the  moisture  surrounding 
the  roots  influences  the  osmotic  pressure,  and  conse- 
quently the  rate  of  absorption.  It  has  been  stated, 
vide  ante,  that  the  osmotic  pressure  of  electrolytes  is 
equal  to  the  proportion  of  the  contained  molecules  + 
ions,  that  the  weaker  the  solution  the  greater  is  the 
ionic  concentration,  therefore  the  pressure  is  higher 
and  the  absorption  more  rapid  in  consequence. 

The  roots  of  a  plant  excrete  certain  acid  excretions 
which  render  soluble  some  of  the  otherwise  insoluble 
mineral  constituents  of  the  soil,  and  thereby  produce 


IONS  IN  PLANTS  33 

the  ions  which  are  so  much  more  readily  absorbed 
than  the  molecules. 

All  the  food  required  by  plants  must  be  in 
solution,  excepting  carbon  and  oxygen,  and,  except- 
ing the  latter,  they  are  all  absorbed  by  the  roots. 
They  are  absorbed  chiefly  as  sulphates,  phosphates 
and  nitrates.  That  they  are  injurious  to  plants  if 
absorbed  in  a  high  state  of  concentration  is  known  ; 
on  the  other  hand,  their  absorption  at  all  by  osmosis 
necessitates  that  the  degree  of  concentration  in  the 
solution  outside  shall  be  higher  than  that  of  the 
interior  of  the  plant ;  whereas  the  more  dilute  the 
solution  the  greater  is  its  ionic  concentration  and 
velocity,  and  consequently  the  greater  the  osmotic 
pressure  and  rapidity  of  absorption. 

Among  the  mineral  substances,  calcium  appears 
to  be  essential  to  the  life  and  functions  of  all  proto- 
plasm, yet  it  is  unknown  in  what  way  it  is  combined 
with  the  essential  basis  of  life.  Another  important 
element,  especially  of  plant  life,  is  potassium  ;  like 
calcium,  it  is  obtained  from  the  soil ;  without  it  the 
absorption  of  C02  and  assimilation  of  carbon  does 
not  go  on,  and  the  plant  does  not  increase  in  weight. 
All  plants  which  are  rich  in  starch  or  sugar  contain 
an  abundance  of  potash  salts  ;  and  it  appears  that 
chlorophyll  is  unable  to  take  up  C02  and  fix  the 
carbon,  except  in  the  presence  of  potassium. 
Chlorophyll  is  only  formed  by  the  leaves  of  plants 
when  iron  is  being  absorbed  from  the  soil ;  and  it  is 
the  combination  of  a  ferric  or  ferrous  ion  with  the 
chloroplastid  which  enables  the  plant  to  utilise  the 
CO2  absorbed  by  the  leaves.  Under  the  influence  of 
the  sun's  rays  C02  absorbed  from  the  air  and  H2O 

3 


34  THE  THEOKY  OF  IONS 

absorbed  by  the  roots  are  dissociated  into  ions  which 
are  united  in  the  chloroplastid  to  form  a  carbohy- 
drate molecule,  thus  :  C02  +  H20  =  CH20  +  02.  This 
is  the  first  stage  in  the  formation  of  starch  and  sugar, 
and  it  is  never  performed  except  by  plants  containing 
chlorophyll  and  in  the  presence  of  potash  salts. 
Potassium  takes  no  direct  part  in  the  process,  but  it 
has  a  well-marked,  indirect  effect,  and  the  process 
is  a  more  intricate  one  than  is  indicated  by  the 
equation.  CH20  may  be  formed  by  a  combination 
of  CO  and  H  ions  ;  but  peroxide  of  hydrogen  is  pro- 
duced from  water  by  the  sun's  rays,  therefore 
hydroxyl  or  OH  ions  may  take  a  part  in  the  process. 
Such  constructive  work  cannot  be  done  without 
energy  ;  and  the  plant  avails  itself  of  the  kinetic 
energy  of  the  sun's  rays,  which  is  the  force  dis- 
sociating C02  and  H20  into  ions.  Plants  without 
light  -and  protoplasm  without  chlorophyll  are  unable 
to  construct  starch  or  sugar  from  these  materials  ; 
and  animals  or  parts  of  plants  which  do  not  contain 
chlorophyll  must  derive  their  carbon  for  constructive 
purposes  from  more  complex  compounds  or  already 
organised  material.  Out  of  the  simple  plastic 
molecule  containing  C,  H,  and  0  more  complex 
substances  are  formed  by  polymerisation  and  con- 
densation of  the  simple  molecules  ;  and  the  process 
by  which  these  compounds  are  united  is  a  complex 
one,  which  results  in  the  formation  of  starch,  sugar, 
cellulose  or  fat. 

Starch  is  an  insoluble  material  which  is  formed  in 
the  leaves  of  plants  and  deposited  therein.  When 
it  is  carried  from  place  to  place  for  nutrition,  growth 
or  storage,  it  is  converted  under  the  influence  of  an 


CONSTRUCTIVE  PROCESSES  35 

enzyme  into  soluble  carbohydrates — glucose,  laevu- 
lose,  or  maltose  ;  the  route  is  determined  by  the 
demand  for  them,  and  the  mode  of  distribution  is 
by  diffusion.  Where  a  tuber  begins  to  sprout  the 
starch  is  drawn  upon  for  constructive  purposes, 
and,  being  converted  to  sugar,  travels  to  the  growing 
points  of  the  young  shoots,  and  supplies  a  large 
portion  of  the  plastic  material  necessary  for  growth. 
Sugar  is  formed  by  the  hydrolysis  of  carbohydrates 
by  acids  or  alkalies.  Hydrolysis  by  alkalies  is  due 
to  the  presence  and  influence  of  OH  ions  ;  hydrolysis 
by  acids  to  free  H  ions  ;  the  former  is  a  slow,  the 
latter  a  comparatively  rapid  process.*  In  the  con- 
version of  starch  to  sugar  by  ptyalin,  or  other 
cellular  enzyme,  the  hydrolysis  is  probably  per- 
formed by  ionisation  in  a  similar  manner.  Inulin  is 
not  converted  to  sugar  by  enzymes  such  as  ptyalin 
or  amylopsin,  and,  when  consumed  by  animals,  its 
conversion  takes  place  in  the  stomach  by  aid  of  the 
acid  ions.f  Many  changes  are  produced  in  the  salts 
contained  by  the  sap  of  plants  ;  during  these  changes 
free  CO,  OH,  H,  0,  C03,  N03,  S04,  P04,  C204, 
C2H302,  and  other  ions  are  constantly  present  from 
the  breaking  down  of  organic  or  inorganic  substances, 
and  the  free  ions  assist  in  the  transformation  of  carbo- 
hydrates from  one  form  to  another.  Fatty  bodies 
are  abundant  in  many  cells,  especially  in  animal  fat, 
vegetables,  seeds  and  fruit.  They  are  formed  by  the 
union  of  a  fatty  acid,  such  as  oleic  or  palmitic  acid 
with  glycerine,  during  which  combination  the  fatty 
acid  replaces  three  hydroxyl  ions  split  off  from  the 

*  Abstracts,  Jour.  Chem.  Soc.,  1898,  714. 
t  Wroblewski:  Zeit.  fur  Physiol.  Chem.,  1898,  xxiv.,  73. 

3—2 


36  THE  THEORY  OF  IONS 

glycerine.  In  the  digestion  of  fat  by  animals,  the 
fats  are  split  up  into  a  glyceryl  radical  and  a  fatty 
acid  radical ;  the  glyceryl  radical  is  joined  by 
OH  ions  and  forms  glycerine  ;  the  fatty  acid  radical 
unites  with  ions  of  Na,  K,  or  Mg,  and  forms  stearate, 
oleate  or  palmitate  of  those  elements,  in  which 
condition  they  are  absorbed.  After  their  diffusion 
into  the  blood-stream  or  while  in  the  interior  of 
cells  forming  a  part  of  the  alimentary  system,  the 
glycerine  and  soap  are  again  dissociated  and  their 
radicals  reunite  to  form  fat. 

In  biological  processes  heat  is  disengaged  during 
chemical  action  just  as  it  is  observed  to  be  in 
non-biological  processes.  Metabolism  consists  of 
anabolic  and  catabolic  changes  in  which  the  heat 
disengaged  is  measurable  in  calories  or  heat  units. 
The  consumption  and  oxidation  of  proteid,  fat,  and 
carbohydrate  results  in  the  liberation  of  known 
quantities  of  heat.  Other  chemical  processes  in  an 
organism  also  result  in  the  liberation  or  consumption 
of  heat  and  energy  which  is  not  always  considered 
in  problems  of  metabolism.  The  neutralisation  of 
an  alkali,  the  conversion  of  organic  acids  to  alkaline 
carbonates,  the  reduction  of  proteids  to  urea  or 
other  waste  products,  of  fat  to  carbonic  acid  and 
water,  are  all  attended  by  the  disengagement  or 
absorption  of  heat.  This  is  in  accordance  with  the 
physical  law  that  matter  and  energy  are  indestruct- 
ible. When  a  chemical  action  takes  place  between 
two  substances  the  total  quantity  of  matter  and 
energy  remains  the  same.  The  equation  C  +  02  = 
C02  shows  only  the  rearrangement  of  the  atoms, 
i.e.  that  when  12  grammes  of  carbon  are  united 


EVOLUTION  OP  HEAT  37 

with  32  grammes  of  oxygen  they  form  44  grammes 
of  carbon  dioxide.  But  just  as  there  is  a  rearrange- 
ment of  the  matter  so  is  there  a  rearrangement  of 
the  energy.  Clerk  Maxwell  in  his  book  on  "  Matter 
and  Motion  "  says  :  "  The  total  energy  in  any 
material  system  is  a  quantity  which  can  neither  be 
increased  nor  diminished  by  any  action  between  the 
parts  of  the  system,  although  it  may  be  transformed 
into  any  of  the  forms  of  which  energy  is  susceptible." 
Thus,  in  electrical  conductivity  the  potential  energy 
of  the  molecules  becomes  kinetic,  the  molecules  are 
split  into  ions,  and  the  energy  takes  a  new  form, 
which  is  positive  or  negative  electricity.  Again, 
during  the  formation  of  carbon  dioxide  from  carbon 
and  oxygen,  12  grammes  of  carbon  require 
32  grammes  of  oxygen  for  the  formation  of 
44  grammes  of  C02 ;  but  the  potential  energy  of 
these  amounts  of  carbon  and  oxygen  is  more  than 
is  retained  by  the  carbon  dioxide,  and  the  excess  is 
transformed  into  97,000  calories  or  units  of  heat ; 
therefore  C  +  02  =  C02  +  97,000  calories.  The  heat 
disengaged  during  the  combination  of  two  or  more 
elements  is  sometimes  called  the  heat  of  formation  ; 
and  many  other  instances  can  be  given  of  the  trans- 
formation of  energy  into  heat  during  chemical  action. 
A  familiar  instance  in  biology  is  the  transformation 
of  organic  acids  to  alkalies  or  alkaline  carbonates. 
In  this  process  ions  are  dissociated,  e.g.  acetates 
contain  the  ion  acetoxyl  C.^fi^O^.  During  the  union 
of  acids  and  alkalies  energy  is  liberated  which  is 
transformed  into  heat ;  from  the  ionic  standpoint 
the  heat  arises  from  the  formation  of  water  by  the 
union  of  H*  and  OIT  ions.  The  liberated  energy  is 


38  THE  THEORY  OF  IONS 

ascertainable,  and  is  called  the  heat  of  neutralisation, 
as  in  the  following  thermo-chemical  equation. 

HC1  +  NaHO  =  NaCl  +  H20  + 13736  or  13'736  calories. 

When  glycero-phosphoric  acid  is  neutralised  by 
sodium  hydroxide  there  is  developed  + 14-95 
calories  for  the  first  equvialent,  +13-75  for  the 
second,  and  +0-1  for  the  third  equivalent;  when 
potassium  hydroxide  is  substituted  the  values  are 
+  15-9,  +13-9  and  +0-4  calories  for  the  same 
equivalents  ;  and  when  phosphoric  acid  is  used  the 
caloric  equivalents  are  practically  the  same.* 

In  all  biological  processes  heat  is  developed  in  a 
similar  manner,  that  is  by  the  transformation  of 
the  energy  possessed  by  ions  in  excess  of  that 
retained  by  the  combined  molecules.  When 
1  gramme  of  fat  is  oxidised  to  C02  and  water,  the 
potential  energy  of  the  fat  is  transformed  into 
kinetic  energy,  and  is  equivalent  to  the  chemical 
force  necessary  to  form  C02  and  water +  9, 300  or 
9-3  calories  or  units  of  heat.  Proteid  and  carbo- 
hydrate are  not  directly  reduced  to  the  low  stage  of 
chemical  constitution  in  which  they  leave  an 
organism  ;  but  the  amount  of  energy  lost  in  the 
form  of  heat  is  the  same  as  if  they  were  directly 
transformed. 

Under  the  influence  of  living  matter,  substances 
more  complex  than  sugar  or  starch  are  formed. 
Organic  compounds  arise  which  contain  N,  S,  P, 
and  other  elements  in  more  and  more  complex 
combination,  until  finally  protoplasm  is  formed. 
But  the  formation  of  nitrogen  compounds  can  only 

*  Imbert  and  Belugon  :  Compt.  Eendus,  1897,  cxxv.,  1040. 


THE  PROTEINS  39 

take  place  when  nitrogen  is  being  taken  up  by  the 
organism.  The  mystery  of  their  formation  is  by 
no  means  elucidated  yet,  although  many  workers 
are  endeavouring  to  throw  light  on  the  subject  by 
organic  analysis  and  synthesis.  In  plants,  nitrogen 
is  taken  up  as  nitrates  and  compounds  of  ammonia.* 
When  sulphate  of  ammonia  is  used  as  a  manure  it 
is  reduced  to  nitrate  before  it  is  absorbed.  The 
nitro-bacteria  of  the  soil  transform  ammonia  com- 
pounds first  to  nitrites  and  then  nitrates.  Most 
plants  are  unable  to  assimilate  uncombined  nitrogen. 
But  peas  and  beans  will  flourish  in  a  soil  which  is 
quite  free  from  nitrogen  compounds  ;  their  roots  and 
tubercles  contain  nitrifying  bacteria  which,  in  the 
presence  of  a  non-nitrogenous  substance  like  glucose, 
can  form  nitrogenous  compounds  from  the  nitrogen 
of  the  air  ;  and  such  nitrogenous  substance  will  be 
absorbed,  f  The  plants,  however,  only  absorb 
nitrogen  in  the  form  of  ammonia  and  nitrates  in  a 
very  dilute  solution,  which  contains  molecules  and 
ions  from  which  the  plants  construct  nitrogenous 
substances  under  the  influence  of  the  protoplasm  or 
enzymes  of  the  cells. 

The  first  organic  nitrogenous  substances  produced 
are  amino-acids,  and  these  are  the  basis  of  the  whole 
series  of  protein  substances.  Proteins  consist  of 
molecules  of  enormous  complexity,  or  long  chains  of 

*  NO'  ions  from  certain  nitrates  joined  with  H'  ions  form 
hydroxylamine,  which  is  a  base  and  may  be  regarded  as  ammonia 
in  which  one  of  its  hydrogen  atoms  has  been  replaced  by  an 
OH  ion,  the  formula  being  NH2(OH).  Salts  are  formed  from 
it  by  direct  union  with  acids,  without  elimination  of  water. 
This  is  an  example  of  the  formation  of  simple  nitrogen  com- 
pounds in  plants. 

f  Vine's  "  Botany." 


40  THE  .THEORY  OF  IONS 

relatively  simple  molecules,  which  can  be  split  by 
hydrolysis,  resulting  in  the  production  of  amino-acids. 
During  recent  years  Fischer,  Siegfried  and  others 
have  been  able  to  unite  synthetically  the  amino- 
acids  into  longer  or  shorter  chains,  that  is  of  trans- 
forming them  or  constructing  amide-like  anhydrides 
with  the  formation  of  peptides  and  polypeptides 
having  the  same  properties  and  reactions  as  the 
natural  peptones.*  The  synthesis  of  peptones  and 
albumoses  in  the  laboratory  may  therefore  be  looked 
for,  and  this  will  probably  throw  light  upon  the 
mode  of  proteid  construction  in  the  living  organism. 
The  whole  series  of  proteins  appears  to  consist  of 
amino-acids,  but  these  are  grouped  into  chains 
which  vary  both  quantitatively  and  qualitatively. 
The  importance  of  the  amino-acids  is  very  great ; 
some  of  the  acids  being  present  in  all  and  others 
in  most  proteins. 

If  little  is  known  of  the  formation  of  protein  bodies 
in  living  organisms  there  is  evidence  to  show  that 
the  assimilation  of  nitrates,  sulphates  and  phos- 
phates containing  the  necessary  elements  for  protein 
formation  can  only  take  place  in  plants  in  the 
presence  of  light ;  and  that  the  first  stage  in  protein- 
formation  by  plants  is  the  production  of  the  com- 
paratively simple  amino-acids,  leucin  and  asparagin. 
The  next  step  is  the  formation  of  the  protein  mole- 
cule, in  the  construction  of  which  the  amino-acids 
occupy  such  an  important  place.  It  is  conceivable 
that,  besides  the  amide-like  chains,  other  modes  of 
union  of  the  elements  of  the  protein-molecule  occur, 

*  Prof.  Barker's  address  at  British  Medical  Association  meet- 
ing, Toronto,  1906. 


THE  PROTEINS  41 

as  piperazin  rings  and  ester  or  ether  groups,  resulting 
from  the  formation  of  intra-molecular  anhydrides 
dependent  upon  the  presence  in  the  oxy-amino- 
acids  of  hydroxyls  (OH'  ions).*  The  formation  of 
protein  is  a  complicated  process,  probably  consisting 
of  a  series  of  assimilatory  additions  to  the  molecule, 
whereby  the  amino-acids  form  the  peculiar  com- 
plexes under  construction.  "  In  the  architecture 
of  the  protein-molecule  and  its  derivatives  Nature 
has  attained  her  highest  chemical  performances." 

Where  and  how  the  formation  of  protein  from 
amino-acids  takes  place  is  not  known  exactly,  but 
there  is  evidence  in  vascular  plants  that  it  takes 
place  in  the  leaves.  Emmerlingf  favours  the  theory 
that  in  plants  the  amino-acids  are  formed  from  the 
simple  inorganic  nitrogen  compounds  which  are 
absorbed  by  the  roots.  The  formation  of  asparagin, 
leucin,  and  other  amino-acids  takes  place  chiefly  in 
the  leaves.  They  are  used  in  the  synthesis  of 
albumin  and  other  proteins  ;  but  as  time  goes  on 
the  amount  produced  is  in  excess  of  that  required 
for  leaf-production,  and  is  used  up  in  the  develop- 
ment of  seeds.  In  plants  nitrogenous  substances 
travel  in  the  form  of  amino-acids  and  amides  from 
one  part  to  another.  In  their  construction  or  trans- 
formation from  one  grade  to  another  ions  are 
doubtless  formed  and  utilised  for  chaining  groups 
together.  Ions  are  the  vehicles  of  energy,  whether 
it  be  of  the  nature  of  electricity,  chemical  energy, 
or  a  more  subtle  vital  force,  and  their  presence  most 

*  Prof.  Barker's  address  at  British  Medical  Association  meet- 
ing, Toronto,  1906. 

f  Lander.  Versucks.-Stat.,  1900,  liv.,  215. 


42  THE  THEORY  OF  IONS 

decidedly  exercises  a  beneficent  influence  upon  the 
process  of  construction,  which  apparently  has  its 
ne  plus  ultra  in  the  production  of  cellular  protoplasm 
endowed  with  powers  of  reproduction,  and  those 
higher  functions  which  are  the  characteristics  of 
brain  and  mind. 

Animals  are  quite  unable  to  assimilate  unorganised 
nitrogen  ;  and  we  do  not  know  exactly  how  they 
assimilate  or  construct  out  of  organised  nitrogenous 
material  the  proteins  of  the  body.  We  know,  how- 
ever, that  each  animal  has  its  own  specific  proteins  ; 
and  that  the  protein  molecules  of  its  food,  including 
edestin,  gliadin,  hordeolin,  zein,  legumin,  hsematin, 
globulin,  casein,  egg-albumin  and  serum-albumin, 
are  not  assimilated  in  these  forms,  but  are  foreign 
to  the  organisation  of  the  consumer  and  could  not 
be  directly  used  for  cell  metabolism.  The  proteins 
in  the  composition  of  each  animal  maintain  a  con- 
stancy of  constitution  and  composition,  no  matter 
what  kind  of  protein  is  consumed.  If  serum-protein 
of  one  animal  were  injected  into  the  blood  of  another 
animal  it  would  lead  to  the  formation  of  precipitines, 
and  would  not  amalgamate  directly  with  the  serum 
of  the  animal  into  which  it  was  injected.*  Digestion 
is  necessary  therefore  not  merely  to  render  protein 
absorbable,  but  to  break  down  the  foreign  protein 
brought  to  the  organism  as  food,  during  which 
process  a  number  of  amino-acids  appear.  The 
proteins  of  each  animal  and  tissue  are  peculiar  to  it ; 
there  must  therefore  be  some  means  by  which  the 
organism  is  rendered  independent  of  the  kind  of 
protein  supplied.  A  child  fed  on  milk  constructs 

*  Barker's  address  :  Brit.  Med.  Jour.,  1906,  ii.,  1093-1110. 


THE  PROTEINS  43 

out  of  it  all  the  proteins  of  its  body.  The  blood 
contains  a  constant  amount  of  serum-albumin  and 
serum-globulin  just  as  it  contains  a  constant 
amount  of  sugar  ;  and  these  are  constructed  from 
the  free  amino-acids  resulting  from  the  hydrolysis 
of  protein  in  the  food.  It  is  not  possible  to  detect 
the  presence  of  free  amino-acids,  albumoses  or 
peptones  in  normal  blood  ;  but  the  foreign  proteins 
are  broken  down  to  these  forms  by  digestion  and 
are  reconstructed  apparently  by  the  cells  of  the 
alimentary  canal  into  cellular  proteins,  and  from 
this  source  a  supply  of  the  specific  proteins  of  the 
blood  is  kept  up,  no  matter  how  foreign  in  nature  is 
the  protein  substance  consumed  as  food. 

In  a  similar  manner  the  individual  cells  of  the 
tissues  also  probably  build  up  their  specific  proteins. 
Barker*  says  there  is  much  evidence  of  a  local 
hydrolysis  in  the  cellular  tissues,  by  which  means  the 
proteins  of  the  serum  are  in  turn  broken  down  to 
amino-acids  which  are  transformed  into  the  special 
amino-acids  required  for  constructing  proteins 
according  to  their  own  pattern.  How  this  is  done 
is  not  exactly  known.  It  is  said  that  all  proto- 
plasmic cells  contain  enzymes  by  which  the  catalytic 
process  is  performed.  But  granting  that  cellular 
enzymes  break  down  the  protein  molecules  in  con- 
tact with  them  into  fragments  or  "  building-stones," 
as  the  amino-acids  have  been  called,  how  from  such 
fragments  do  the  cells  make  up  the  arginin  required 
to  build  histone  for  the  thymus,  glycocoll  to  build 
up  elastin,  leucin  and  glutaminic'  acid  for  serum- 
albumin,  aspartic  acid  for  keratin,  etc  ?  What  is 

*  Barker's  address  :  Brit.  Med.  Jour.,  1906,  ii.,  1093-1110. 


44  THE  THEORY  OF  IONS 

the  influence  which  produces  these  architectural 
changes  ?  Is  it  a  chemical  action  resulting  from 
the  splitting  of  molecules  into  ions  ?  We  have  been 
informed  that  substances  consisting  of  a  high  pro- 
portion of  polymerised  molecules  cannot  readily 
form  ions,  and  that  other  substances  with  large  di- 
electric constants  but  small  polymerisation  are 
unsuitably  constituted  for  ionisation  in  the  ordinary 
way.*  Nevertheless,  as  all  constructive  processes 
depend  upon  the  formation  of  molecules  or  atoms  of 
matter  in  an  active  condition  (ions  being  matter  in 
an  active  form),  the  fragments  of  protein  which  are 
split  up  must  remain  in  an  active  condition,  other- 
wise reconstruction  would  not  take  place.  Highly 
polymerised  molecules  are  split  up  by  ferments  or 
enzymes,  which  sometimes  take  part  in  their  recon- 
struction. It  is  thus  that  emulsin  and  myrosin  act 
in  the  formation  of  prussic  acid  and  volatile  oil  of 
mustard.  Emulsin  splits  the  glucoside  amygdalin 
into  ions  or  other  fragments,  which  reunite  to  form 
the  essential  oil  of  almonds,  free  prussic  acid,  formic 
acid  and  glucose.  All  cellular  substances  are 
believed  to  contain  such  enzymes  ;  by  their  aid 
serum-proteins  are  split  into  amino-acids,  and 
active  ions  such  as  CO,  OH,  H,  NH2  and  others 
link  them  together  and  form  new  complexes  in 
which  the  enzyme  itself  very  likely  forms  a  central 
figure.  All  the  amino-acids  contain  one  or  more 
asymmetrical  atoms  of  carbon,  and  nearly  all  such 
acids  have  been  manufactured  in  the  laboratory. 
The  same  kinds  of  amino-acids  are  present  in  nearly 
all  animal  and  vegetable  proteins,  but  as  their 
*  Abegg :  loc.  cit. 


THE  PROTEINS  45 

proportion  varies  so  does  the  composition  and 
character  of  the  proteins  ;  and  the  proportion  of 
amino-acids  which  can  be  obtained  from  proteins 
affords  no  clue  to  the  mode  of  their  arrangement  in 
the  protein  molecule.*  Albumoses  and  peptones  are 
units  in  the  protein  molecule  of  much  higher 
chemical  constitution  than  the  amino-acids  from 
which  they  are  derived,  indeed  their  constitution 
is  nearly  as  obscure  and  complex  as  that  of  protein 
itself.  Recently  Fischer  has,  by  chemical  action, 
chained  together  the  amino-acids  into  substances 
called  peptides  and  polypeptides  which  give  the 
biuret  reaction  like  true  or  natural  peptones.  A 
continuance  of  such  synthetic  processes  will  probably 
throw  light  on  the  mode  of  protein-formation  in  the 
living  organism. 

*  Barker :  loc.  cit. 


IV.— EVOLUTION  OF  ORGANIC  MATTER 

THE  vortex-atom  theory  assumes  that  the  universe 
consists  of  a  uniform  primary  substance ;  and  that 
what  we  call  matter  consists  of  portions  of  this 
substance  which  have  become  animated  with  vortex 
motion.  This  is  the  theory  of  Helmholtz,  and  it 
receives  the  support  of  Kelvin,  Tait  and  other 
eminent  physicists.  The  atoms  are  supposed  or 
believed  to  be  in  the  form  of  vortex  rings,  each  of 
which  is  distinct  in  mass,  form  and  motion,  and  is 
indestructible.  The  rings  of  smoke  formed  by 
tobacco-smokers  have  often  been  used  as  illustrating 
such  vortex  action  ;  the  particles  of  such  rings  are 
revolving  in  small  circles  at  right  angles  to  the  axis 
or  circumference  of  the  larger  circle  or  ring.  Such 
rings  have  stability,  although  they  bend,  recede, 
enlarge,  and  are  capable  of  intussusception,  as  they 
are  moulded  by  the  movements  of  the  air  or  other 
such  rings  which  come  into  contact  with  them. 
They  ultimately  burst  because  they  meet  with  re- 
sistance from  the  circulating  air.  If  they  were  free 
from  all  friction,  such  rings  would  be  indivisible  and 
indestructible.  Such  is  supposed  to  be  the  nature 
of  atoms  and  their  movements.  The  atoms  form 
molecules,  and  although  the  molecules  are  diversified, 
all  the  forms  of  matter  are  simply  combinations  of 

46 


VORTEX-ATOM  THEORY  47 

so  many  vortex  rings,  distinct  and  indestructible 
in  form  and  motion. 

Since  the  discovery  of  radio-activity  physicists, 
led  by  Larmor,  now  conceive  that  each  atom,  like 
the  ring  of  smoke,  consists  of  still  smaller  particles, 
electrons  or  metabolons,  with  which  the  energy  is  asso- 
ciated. These  smaller  particles  convey  the  energy 
and  are  the  source  of  the  electrical  condition  of  the 
atom.  What  they  are  is  still  unknown.  Their 
close  association  with  force,  and  the  origin  of  matter 
from  one  primal  substance,  favours  the  idea  that 
they  are  the  same  as  the  ether.  The  atomic  con- 
stitution of  the  ether  has  been  admitted,  and  it  is 
by  many  authorities  considered  to  be  the  primal 
substance,  or  at  any  rate  to  form  the  substratum  of 
matter.  It  is  also  thought  that  it  is  the  electrons 
which  cause  the  wave-movements  in  ether  which 
we  recognise  as  heat  and  light.  Further,  the  atomic 
weight  of  the  elements  varies  with  the  number  of 
electrons  in  an  atom  ;  an  atom  of  hydrogen  is  said 
to  contain  1,000,  while  that  of  mercury  consists  of 
100,000  electrons. 

Atoms  are  endowed  with  polarity,  which,  being 
aided  by  affinity,  quantivalence,  atomicity  and 
isomerism,  gives  a  clue  to  the  construction  of 
inorganic  and  organic  matter  which  is  built  up  by 
polar  forces.  Polarity  is  a  term  used  to  express 
briefly  the  generally  observed  fact,  called  the 
principle  of  polarity,  that  when  energy  changes  from 
the  passive  to  the  active  form,  from  potential  to 
kinetic,  it  develops  opposite  and  conflicting  forces. 
There  is  no  action  without  a  contrary  and  equal 
reaction,  no  attraction  without  repulsion,  no  positive 


48  THE  THEORY  OF  IONS 

without  a  negative.  The  simplest  example  of 
polarity  is  seen  in  the  magnet.  It  pervades  the 
material  and  immaterial  universe. 

The  elements  exhibit  this  polarity  in  different 
ways.  It  may  be  like  that  of  a  magnet,  in  which 
there  are  two  poles  and  two  only.  Thus,  oxygen  is 
bipolar  and  capable  of  attracting  to  itself  two  ions 
of  hydrogen  to  form  a  molecule  of  water.  Hydrogen 
on  the  other  hand  is  unipolar,  and  the  ion  only 
attracts  and  holds  a  single  ion  of  chlorine  to  form 
a  molecule  of  HC1.  Chlorine  is  also  unipolar.  The 
H  ion  is  positive,  the  Cl  ion  carries  a  negative 
electrical  charge.  An  element  having  a  single  pole 
must  create  the  opposite  pole  by  induction  in 
another  body.  The  analogy  between  atomic  or 
electrical  and  magnetic  polarity  can  be  rendered 
evident  by  pith-balls.  If  a  pith-ball  charged  with 
positive  electricity  is  brought  near  to  a  negatively 
charged  one,  they  mutually  attract  one  another, 
and  each  becomes  the  pole  of  the  other.  Separated 
to  a  distance  each  carries  its  own  charge,  and  they 
no  longer  influence  each  other  ;  but  each  draws  an 
opposite  electrical  charge  from  the  nearest  conductor, 
and  thus  creates  for  itself  the  opposite  pole.  Simi- 
larly, when  a  glass  rod  is  rubbed  with  silk,  it  becomes 
positively  electrified,  and  induces  the  opposite  kind 
of  electricity  in  the  silk.  Polarity  involves  the 
opposition  of  two  relations  or  poles  which  attract 
each  other ;  this  is  an  indispensable  condition. 
Electrical  polarity  differs  from  magnetic  polarity  in 
the  fact  that  in  magnetic  polarity  both  poles  arejn 
one  body,  in  electric  polarity  they  are  in  separate 
bodies. 


POLARITY  OF  MATTER  49 

This  exhibition  of  polarity  by  the  elements  is 
called  their  valency  or  chemical  affinity  ;  and  the 
elements  are  unipolar,  bipolar,  or  multipolar,  accord- 
ing as  each  atom  has  the  power  of  attracting  or 
combining  with  one  or  more  atoms.  It  is  as  though 
each  atom  were  a  magnet,  with  one  or  more  poles 
by  which  other  atoms  are  attracted  or  attached  to 
it.  These  valencies  or  poles  have  a  strong  craving 
for  satisfaction,  called  saturation  ;  so  great  is  their 
attraction  that  they  seize  upon  their  own  kind  when 
no  other  element  is  free,  or  they  will  displace  atoms 
from  some  other  combination  to  form  molecules. 

The  valency  of  the  ions  may  therefore  be  repre- 
sented as  the  poles  of  attraction,  and  each  ion  is  a 
monad,  dyad,  triad,  tetrad,  or  pentad,  according  to 
the  number  of  poles  of  attraction,  valencies,  or 
affinities  it  exhibits.  Arranged  in  this  manner  the 
ions  can  be  classified  according  to  the  following 
examples  : 

A. — Cations. 

1.  MONADS  :  Monovalent  or  unipolar  ions — e.g., 

H  (in  acids),  NH4,  K,  Na,  Li, 
Ag,  also  Hg  (mercurous)  and 
Cu  (cuprous). 

2.  DYADS  :  Divalent  or  bipolar  ions,  as  Mg,  Ca, 

Fe  (ferrous),  Ba,  Sr,  S,  Zn,  Pb, 
also  Cu  (cupric)  and  Hg  (mer- 
curic). 

3.  TRIADS  :  Trivalent  or  tripolar  ions,  as  Fe 

(ferric),  Al,  Bi,  Sb. 


50  THE  THEORY  OF  IONS 

B. — Anions. 

1.  MONADS  :    OH,   F,    Cl,    Br,   I,    N03,   C103, 

C2H302    and     the    anions     or 
radicals  of  all  monobasic  acids. 

2.  DYADS  :    S04,  S03,  S203,  C03,  S  (sulphide), 

C204,  and  all  anions  of  dibasic 
acids. 

3.  TRIADS  :  P04,  and  anions  of  all  tribasic  acids. 

The  amount  of  the  electrical  charge  carried  by 
the  ions  varies  with  the  valency  of  the  element  or 
elements,  as  before  stated.  Thus,  1  gramme- 
molecule  of  H  ions  carries  a  charge  of  positive 
electricity  estimated  as  96,550  coulombs.  This  is 
the  standard  of  the  capacity  of  ions  for  carrying 
electricity.  All  monovalent  ions  or  monads  carries 
the  same  in  proportion  to  their  atomic  weight. 
Divalent  ions  or  dyads  carry  twice  as  much,  there- 
fore a  gramme-molecule  of  calcium  ions  carry 
2  x  96,550  coulombs  of  positive  electricity,  and  each 
ion  would  require  two  ions  of  negatively  charged 
chlorine  to  satisfy  its  valency.  Similarly,  the 
trivalent  nitrogen  ion  would  require  three  ions  of 
hydrogen  to  satisfy  its  valency  or  neutralise  its 
electricity  ;  and  a  gramme-molecule  of  N  ions  would 
carry  3  x  96,550  coulombs. 

It  is  to  be  observed  that  the  valency  of  some  ions 
may  be  changed.  Carbon  may  be  either  dyad  or 
tetrad  ;  sulphur,  a  dyad,  tetrad,  or  hexad  ;  nitrogen, 
a  triad'  or  pentad  ;  phosphorus,  a  triad  or  pentad  ; 
and  chlorine  may  be  monad,  triad,  pentad,  or  hep  tad. 
This  changeable  character  is,  however,  only  shown 
towards  btrdfes  jbh&t  ^,re  -more  eJectm-nega^ive  than 


CHAIN  THEORY  51 

themselves.  Towards  electro-positive  bodies  their 
polarity  or  valency  is  invariable.  Hydrogen  is 
always  a  monad ;  Cl  uniting  with  one  ion-atom  of 
H,  S  with  two,  N  with  three,  C  with  four,  providing 
that  only  one  ion-atom  of  these  elements  enters  into 
the  combination. 

The  bond  between  two  different  ions  is  not 
always  a  stable  one.  HC1  is  formed  by  the  union  of 
two  monovalent  ions,  of  which  H  is  positive  and 
Cl  strongly  negative.  But  the  H  is  easily  displaced 
by  any  other  positive  ion  for  which  the  Cl  ion  has 
a  greater  affinity,  as  the  dyad  calcium,  or  the  triad 
iron.  Such  displacement  may  be  due  to  the  attack- 
ing ion  carrying  a  greater  charge  of  electricity.  The 
same  displacement  is  observed  in  many  organic  and 
inorganic  molecules.  The  substitution  of  other  ions 
for  H  or  OH  ions  takes  place  with  ease  and  rapidity, 
and  OH  ions  are  themselves  greatly  provocative 
of  such  changes,  whereby  the  character  of  the 
molecule  may  be  very  greatly  altered. 

This  linking  together  of  atoms  or  ions  by  polar 
attraction  and  according  to  their  valency  has  given 
rise  to  what  is  known  as  the  chain  theory  of  molecular 
constitution.  In  the  hydrocarbons,  for  instance, 
methane,  CH4,  is  a  complete  molecule ;  but  it  may  be 
robbed  of  an  atom  of  H  by  a  wandering  OH  ion, 
leaving  methyl,  CH3,  which  is  a  monad,  a  rest,  radical, 
or  link,  having  one  unsatisfied  valency.  CH4  might 
be  robbed  of  two  H  atoms,  leaving  the  rest,  CH2,  and 
a  divalent  ion.  Such  rests  or  links  do  not  exist  in 
a  free  state,  they  are  ions  demanding  companionship. 
They  attract  other  ions,  rests  or  links,  or  even 
displace  an  atom  or  a  link  from  some  other  molecule 

4—2 


52  THE  THEORY  OF  IONS 

and  join  it  to  form  a  chain.  These  are  straight  or 
open  chains  and  cylo  or  closed  chains  or  rings,  of 
which  examples  are  here  given.  If  H  atoms  are 
removed  from  the  ends  of  the  straight  chain,  and 
the  free  valencies  of  the  carbon  are  not  satisfied 
by  union  with  another  ion,  they  bend  over  until 
they  meet  and  form  a  ring.  Side  chains  are  formed 
by  another  radical  or  rest  dislodging  one  or  more 
H  atoms  from  such  a  ring.  H  is  represented  by  the 
open  circle  and  C  by  the  closed  one. 


6      6 

Hexane,  C6H14 

9 


*« 


o. 


6  666 


Benzene-hexa-  Cyrnene-hexa- 

hydride,  C6H12  hydride,  C10H20 

The  importance  of  ions  in  the  physiological 
economy  of  plants  and  animals  is  strikingly  evident. 
Animals  are  dependent,  herbivora  directly  and  carni- 
vora  indirectly,  upon  plant  life  for  the  chief  elements 
of  their  sustenance,  viz.,  proteins,  carbohydrates  and 


EVOLUTION  OF  CARBOHYDRATES      53 

fats.  It  is  therefore  to  the  plants  that  we  should 
look  for  their  formation.  These  bodies  take  their 
rise  from  a  few  simple  combinations  of  ions  dis- 
sociated from  C02  and  water  ;  from  which,  together 
with  ions  from  ammonia  compounds,  nitrates,  and 
a  few  other  salts,  the  plant  builds  up  the  complicated 
substances  of  its  organism.  An  endeavour  is  here 
made  to  give  an  idea  of  their  evolution  or 
development. 

The  synthetic  processes  are  started  from  the 
dissociation  of  carbonic  dioxide  and  water  by  the 
energy  of  sunlight  into  CO,  OH,  H,  and  0  ions. 
The  equation  CO2  +  H20  =  CH20  +  02  represents  in 
gross  what  takes  place  in  the  leaves  of  the  plant. 
But  the  intermediate  stages  are  not  represented  and 
the  knowledge  of  them  is  not  quite  so  clear.  Under 
the  influence  of  the  sun's  rays  hydrogen  peroxide, 
H202,  is  formed,  which  may  split  into  OH  ions  ;  or 
water  may  be  directly  split  into  H  and  OH  ions. 
Again  an  O  ion  may  be  split  off  from  C02,  leaving 
the  CO  ion  or  carbonyl.  Now  CO+OH  =  CO-OH 
or  carboxyl,  which  is  an  anion,  and  an  acid  radical 
formed  in  the  construction  of  the  molecules  of  all 
organic  acids. 

CO-OH  +  OH  =  CH(OH)  +  02  or  CH2O  +  02. 

The  O  atom  in  the  carbonyl  ion  CO  may  be  dis- 
placed by  an  OH  ion,  thereby  forming  CHO,  which 
is  the  aldehyde  index  represented  by 

?0 

the  oxygen  being  shown  as  a  double  circle.  The 
tetrad  carbon  joins  by  two  of  its  poles  or  valencies 


54  THE  THEORY  OF  IONS 

to  the  dyad  or  bipolar  oxygen,  while  one  pole  is 
occupied  by  the  H  atom,  and  the  fourth  valency 
remains  free  and  demands  satisfaction.  CHO  is 
therefore  a  monad  or  monovalent  ion.  Where  this 
is  satisfied  by  an  H  ion  directly,  or  indirectly  through 
displacement  of  the  0  by  an  OH  ion,  we  have  the 
molecule  CH20,  which  is  methyl  aldehyde.  This  has 
a  strong  tendency  to  polymerise  ;  in  fact,  poly- 
merisation is  a  great  characteristic  of  the  aldehydes 
as  a  group.  Thus  when  two  molecules  are  linked 
together  they  form  glycollic  aldehyde,  C2H402 ; 
when  three  molecules  are  linked  together  they  form 
Trioses,  C3H603,  e.g.  glycerose  ;  four  molecules  form 
Tetroses,  C4H8O4,  e.g.  erythose  ;  five  molecules  form 
Pentoses,  C5H1005,  e.g.  arabinose  or  xylose  ;  and  by 
linking  together  six  molecules  we  have  formed  the 
Hexoses  or  Glucoses,  C6H1206,  including  dextrose, 
laevulose,  galactose,  mannose,  acrose,  etc.  Singly 
linked  compounds  of  carbon  containing  hydroxyls, 
besides  the  aldehyde  nucleus,  are  termed  Aldols 
(contracted  from  alcoholic  aldehyde),  and  when  each 
carbon  atom  except  the  aldehyde  nucleus  is  linked 
with  one  hydroxyl  (OH)  it  is  called  a  carbohydrate* 
Thus  : 


Q 

9 

f 

9 

t 

,     1       ,     A 

9 
f 

i  .4 

6 

'  ?  ' 
6 

¥         T 

6 

6 

6 
Dextrose,  CGH1206 

Holler's  "  Chemistry/'  p.  155. 


EVOLUTION  OF  CARBOHYDRATES      55 

The  mono-saccharides  are  aldehydes  or  ketones 
of  polyhydric  alcohols.  The  first  are  aldoses,  e.g. 
dextrose,  C6H1206,  and  the  second  are  ketoses,  e.g. 
laevulose,  which  is  also  C6H1206.  The  difference 
between  them  is  shown  by  the  ionic  linking  or 
structural  formula. 

Dextrose  = 
CH2(OH).CH(OH).CH(OH).CH(OH).CH(OH).CHO 

Lsevulose  = 
CH2(OH).CH(OH).CH(OH).CH(OH).CO-CH2(OH). 

The  mono-saccharides  are  convertible  into  corre- 
sponding alcohols  by  nascent  hydrogen,  i.e.  by  H 
ions  ;  thus  dextrose  and  Isevulose  become  sorbite, 
mannite,  and  dulcite  :  C6H1406.  Inversely  the  corre- 
sponding sugars  may  be  derived  from  the  alcohols 
through  oxidation  by  OH  ions.*  The  pentoses, 
C5H1005,  are  formed  from  more  complex  carbo- 
hydrates by  hydrolytic  splitting  to  form  pentosanes. 
These  are  of  great  importance  in  the  vegetable  king- 
dom as  building  material,  and  consequently  as  food 
for  the  herbivorous  animals.  The  chief  pentoses  are 
arabinose  and  xylose,  the  latter  of  which  is  widely 
distributed  throughout  the  vegetable  kingdom. 

One  of  the  derivatives  of  the  glucoses  (dextrose  or 
mannose)  is  glucosamine,  C6H13N05  or  CH2(OH)- 
CH(OH)-CH(OH).CH(OH).CH(NH2).CHO.  This  is 
an  intermediary  member  between  the  carbohydrates 
(hexoses)  and  the  amino-acids  obtainable  from 
proteids,  and  is  therefore  to  be  regarded  as  a  bridge 
between  the  carbohydrates  and  the  proteids.f 

*  Hammarten's  "  Physiological  Chemistry,"  p.  85. 
t  Ibid.,  p.  98. 


56  THE  THEORY  OF  IONS 

The  di-saccharides  or  Cane-sugar  group  are 
products  of  an  aldose  or  alcoholic  aldehyde  and  a 
ketose  in  such  a  way  that  there  is  a  loss  of  a  molecule 
of  water.  Thus  : 

(C6H1206  -  H)  +  (C6H1206  -  OH)  -  C12H22On  +  H20. 

Dextrose  Laevulose  Cane-sugar 

Maltose  consists  of  two  molecules  of  dextrose 
linked  together,  with  loss  of  water  ;  and  lactose  of  a 
molecule  of  dextrose  and  a  molecule  of  galactose, 
also  linked  together  with  loss  of  (H  +  OH)  a  molecule 
of  water. 

The  poly-saccharides,  amyloses,  or  cellulose  group 
are  likewise  formed  by  linking  together  more  than 
three  molecules  of  hexoses  or  glucoses  in  the  sugar- 
cane fashion. 

Glucosides  are  formed  from  dextrose  or  other 
glucoses  and  a  phenol,  by  junction  of  their  alcoholic 
hydroxyls  in  regular  ether-fashion  ;  that  is,  by  one 
of  the  molecules  dropping  an  H  and  the  other  an 
OH  to  form  a  molecule  of  water.  They  can  also  be 
split  into  their  components  by  enzymes  or  by  dilute 
alkalies  and  acids. 

Combinations  of  C  and  H  alone  are  called  hydro- 
carbons. The  simplest  compound  is  that  in  which 
each  of  the  four  valencies  or  poles  of  the  carbon 
atom  is  joined  to  a  hydrogen  atom.  It  is  marsh  gas 
or  methane,  CH4.  The  organic  world  is  constructed 
out  of  this  combination  by  repeatedly  removing  one 
or  more  atoms  of  hydrogen,  and  placing  some 
equivalent  in  their  stead.  This  is  done  by  substitu- 
tion or  replacement.  The  carbon  atom  may  drop  one 


HYDROCARBONS  57 

or  more  atoms  of  H  for  something  for  which  it  has 
a  greater  affinity  ;  or  some  other  ion  more  strongly 
negative  may  be  able  to  displace  the  H  and  occupy 
its  place  ;  thus  the  OH  ion  carries  a  stronger  electro- 
negative charge  than  H.*  Indeed,  OH  ions  play  a 
very  active  part  in  the  molecular  changes  of  an 
enormous  number  of  organic  compounds,  for  by  OH 
displacing  any  H  the  compound  is  indirectly  oxidised. 
If  the  methane  molecule  is  robbed  of  one  of  its 
H  atoms  by  a  migrating  OH  ion  or  any  other  ion 
having  that  power,  it  leaves  the  combination  with  a 
free  valency  which  demands  satisfaction.  What  is 
left  is  methyl,  CH3,  a  monovalent  ion,  which  will 
seize  upon  the  free  valency  of  similar  molecules. 
Ethane  is  formed  by  union  of  two  such  ions,  thus  : 

CH3-CH3  or  2CH4  -  2H  +  20H  =  2H20  +  C2H6. 

But  methane  may  be  stripped  of  two  hydrogen 
atoms,  leaving  CH2,  a  rest  or  divalent  ion  with  two 
unsatisfied  valencies.  These  also  may  be  saturated 
by  joining  ions.  Such  molecules  form  open  chains, 
and  may  be  composed  of  a  number  of  ions  or  links 
of  a  like  character.  In  this  manner  series  of  com- 
pounds are  formed  of  which  the  following  are 
examples  : 

Ethane,    C2H6  =  CH3-CH3. 
Propane,  C3H8  =  CH3-CH2-CH3. 
Butane,    C4H10  =  CH3-CH2-CH2-CH3. 
Pentane,  C5H12  = 
Hexane,    C6H14  - 


*  H  is  positive;  but  some  ions  may  have  their  electrical 
reaction  changed  from  negative  to  positive  or  vice  versa.  The 
acid  anions  are  all  negative  whether  they  contain  H  or  not. 


58  THE  THEORY  OF  IONS 

The  Fats  are  derivatives  of  the  hydrocarbons, 
whence  they  are  called  the  Aliphatic  or  fatty  series. 
The  alcohols  are  also  derived  from  them  by  one  or 
more  OH  ions  displacing  or  being  substituted  in  the 
link  for  the  same  number  of  H  atoms,  and  the 
molecule  is  oxidised.  Thus  : 

Methane,    CH4  +  OH  =  H  +  CH4O,  Methyl  alcohol. 

Ethane,     C2H6  +  OH  =  H  +  C2H60,  Ethyl  alcohol. 
C2H6  +  20H  =  H2  +  C2H602,  Ethylene  al- 
cohol or  Glycol. 

Propane,  C3H8  +  30H  =  3H  +  C3H803,  Glycerine  or 

triacid  alcohol. 

Butane,  C4H10  +  40H  =  2H2  +  C4H1004,  Butyl  alco- 
hol. 

Hexane,  C6H14  +  60H  =  3H2  +  C6H1406,  Mannite. 

Alcohol,  radicals  are  formed  by  removing  one  OH 
from  each  carbon  atom  in  the  structure  ;  such 
radicals  are  monad,  dyad  or  triad  ions  according  to 
the  number  of  valencies  thus  liberated.  They  do 
not  exist  in  a  free  state,  but  migrate  to  join  other 
compounds  by  dehydrating  them,  when  free  OH 
ions  do  not  exist  to  satisfy  their  craving.  It  is  in 
this  manner  that  ethers  are  formed  from  two  mole- 
cules of  alcohol,  the  one  losing  OH  and  the  other  H 
to  form  a  molecule  of  water.  Monovalent  alcohol- 
radicals  are  called  alkyls,  and  divalent  ones  alkylenes. 

Although  the  hydrocarbon  is  oxidised  by  the 
OH  ion  to  alcohol,  the  influence  of  OH  ions  upon  the 
molecule  is  not  ended  ;  it  can  abstract  more  H  atoms 
from  it.  If  the  action  of  the  OH  ion  be  upon  a 
primary  alcohol  the  result  is  the  formation  of  an 
aldehyde. 


FATS  59 

Ethyl  alcohol,  C2H60  +  20H  =  2H20  +  C2H40,  or 
Ethylic  aldehyde. 

If  the  action  be  upon  a  secondary  alcohol,  e.g. 
secondary  propyl-alcohol,  the  result  is  a  ketone, 
di-methyl-ketone,  or  acetone — 

C3H80  +  20H  =  C3H60  +  2H20. 

The  aldehydes  and  ketones  may  be  still  further 
attacked  by  OH  ions,  which,  being  oxidised  thereby, 
are  transformed  into  acids.  In  the  case  of  alde- 
hydes, the  H  belonging  to  the  carbonyl  group  is 
displaced  by  the  hydroxyl ;  e.g. 

Methyl-aldehyde,   CH20  +  20H  =  H20  +  CH202 

or  Formic  acid. 
Ethyl-aldehyde,     C2H40  +  20H  =  H20  +  C2H402 

or  Acetic  acid. 
Propyl-aldehyde,  C3H60  +  20H  =  H20  +  C3H602 

or  Proprionic  acid. 
Butyl-aldehyde,     C4H80  +  20H  =  H20  +  C4H802 

or  Butyric  acid. 

In  a  similar  way  Caproic  acid,  C6H1202,  is  formed 
from  Hexane  or  normal  hexyl-alcohol.  Capric, 
caprylic,  lauric,  myristic,  palmitic,  stearic,  and  oleic 
fatty  acids  are  the  higher  homologues  of  Caproic 
acid. 

The  Fats  are  neutral  compound  ethers  or  esters  of 

fOH 
the  poly-acid  alcohol,  glycerine,  C3H803  or  C3H5 -j  OH. 

IOH 

These  esters  are  tri-glycerides,  that  is,  the  H  atoms 
of  the  three  hydroxyls  are  replaced  by  fatty  acid- 


60  THE  THEORY  OF  IONS 

radicals.*  Fundamental  dibasic  acids  have  two 
carboxyl  groups  in  the  chain,  and  are  formed  by 
removing  hydroxyls  from  these  groups.  In  this 
manner  oxalic  acid  is  derived  from  acetic  acid,  and 
succinic  acid  from  propionic.  When  succinic  acid  is 
oxidised  by  an  OH  ion  displacing  and  taking  the 
place  of  an  H  atom  we  get  malic  acid  ;  by  hydroxyls 

9 
O"®—  — 4-o 


O-4—  —  ®-o 
i 

I 

>•<§)  —  4-0 

^ft 

6 

i  w 

Glycerine  C3H803 

Palmitic  Acid  C16H3,02 

9      91  ^ 

rvA-..  <&   .^m^ 

9 

•—(§)—•  ^'O 

Oil  A               frh            ^4*^ 

H 

,.JAL.._4^O 

U"^  ••  91  ••  w  • 

6     a 

W*  W    -•  —  \&  —  .  «-.^     < 

"  IT  "  T  u 

O        fOl 

1 

1  Al         x*v 

o^JfL^ 

-®-~f~O 

Palinitin  C51H9806 

replacing  two  H  atoms  from  succinic  acid  or  one 
from  malic  acid  we  get  tartaric  acid.  Glycollic  acid 
in  unripe  fruit  is  also  formed  by  the  oxidation  of 
acetic  acid  through  the  action  of  the  OH  ion.  Lactic 
acid  is  formed  by  oxidation  of  propionic  acid  in  this 
way,  and  other  organic  acids  are  formed  in  a  similar 
manner. 

*  Diagrams  from  Holler's  "  Chemistry." 


PHOSPHORUS  COMPOUNDS  61 

Other  elements  may  take  part  in  the  construction 
of  molecules  from  ions  consisting  of  radicals  or  rests. 
Among  the  most  important  substances  absorbed  by 
the  roots  of  plants  are  phosphates,  sulphates,  chlor- 
ides, and  nitrates.  These  salts  exist  in  the  sap  of 
plants  chiefly  in  the  form  of  ions  ;•  e.g.  the  phosphoric 
acid  of  the  phosphates  of  potash  ammonia  or  soda 
absorbed  is  in  the  form  of  a  trivalent  anion,  P04. 
An  important  organic  compound  is  glycero-phos- 
phoric  acid,  C3H9P06,  formed  by  the  acid  ion  joining 
to  the  tri-acid-alcohol  called  glycerine  in  ether 
fashion,  i.e.  by  the  acid  ion  displacing  one  OH  from 
the  glycerine  molecule.  Lecithin,  another  important 
organic  phosphorus  compound,  is  formed  from 
glycero-phosphoric  acid  by  fatty  acids  replacing  the 
other  two  hydroxyls  in  the  glycerine  of  the  com- 
pound. The  fatty  acids  may  be  stearic,  palmitic,  or 
oleic,  one  or  two  kinds.  Lecithin  originates  in 
plants  ;  enters  the  animal  organism,  and  is  found  in 
nearly  all  cellular  structures,  being  the  chief  link 
between  inorganic  and  organised  phosphorus  in  the 
living  body.  Phosphorus  is  pentad  or  pentavalent ; 
phosphoric  acid  is  trivalent.  It  forms  three  kinds  of 
salts,  thus  :  normal  sodium  phosphate,  which  is 
Na3P04,  may  have  one  of  its  Na  atoms  replaced  by 
H  as  in  hydrogen-disodium  phosphate,  HNa2P04,  or 
by  2H  as  in  H2NaP04.  Again,  one  hydrogen  atom 
may  be  displaced  by  another  ion  as  NH4  in  hydrogen- 
sodium-ammonium  phosphate,  HNa(NH4)P04 ;  and 
the  other  Na  atom  may  be  displaced  by  another 
metallic  ion,  e.g.  Mg,  in  the  compound  ammonium- 
magnesium-phosphate,  (NH4)MgP04. 

The  halogens  Cl,  Br  and  I,  form  monovalent  ions 


62  THE  THEORY  OF  IONS 

which  can  displace  hydrogen  from  very  many  of  its 
combinations  and  occupy  the  same  position  in  the 
molecule.  A  large  number  of  halogen  compounds 
derived  from  the  hydrocarbons  are  known  to 
pharmacology.  Thus  CH4  by  displacement  of  H 
may  become  successively  methyl-chloride,  CH3C1, 
methylene  chloride,  CH2C12,  and  chloroform,  CHC13. 
Other  alcohol  radicals  may  likewise  have  their 
hydrogen  displaced,  thus  C2H6  becomes  Ethyl 
bromide,  C2H5Br,  and  Ethylene  Iodide,  C2H4I2.  The 
hydrogen  may  likewise  be  displaced  by  a  halogen- 
compound  ;  thus  C2H6  may  become  C2H5HgCl,  or 
Mercury-ethyl-chloride.  Aldehydes  and  acids  also 
may  have  their  hydrogen  displaced  by  Cl  ions,  thus  : 

Acetic  aldehyde,  C2H40  +  3C1  =  3H  +  C2HC130,  or 

chloral. 
Acetic     acid,     C2H402  +  3C1  =  3H  +  C2HC1302,  or 

Tri-chlor-acetic  acid. 

Sulphur,  like  chlorine  and  phosphorus,  enters  the 
organism  in  the  form  of  an  ion  derived  from  organic 
or  inorganic  compounds.  The  salts  of  the  soil  enter 
the  root-hairs  of  plants  chiefly  as  ions  in  the  dilute 
solution  which  surrounds  them,  and  they  exist 
mainly  in  form  of  ions  in  the  circulating  fluids  of 
the  plants. 

Sulphur  behaves  towards  other  elements  differ- 
ently from  C,  H,  and  0.  The  latter  have  a  certain 
number  of  poles  or  valencies,  no  more  nor  less.  Such 
valencies  represent  the  demand  or  craving  for  union 
with  other  atoms.  Atoms  are  active  ions  until  each 
valency  is  satisfied  ;  and  the  body  is  not  at  rest  or 
the  compound  in  a  stable  form  until  such  poles  are 


SULPHUR  COMPOUNDS  63 

joined  to  other  poles  of  attraction.  Thus  H  is  a 
monad  ion  in  all  circumstances  ;  oxygen  is  always  a 
dyad  ;  and  carbon  is  a  tetrad  in  all  its  relations  to 
hydrogen.  The  halogens,  however,  are  only  monads 
in  their  combinations  with  ions  more  electro-positive 
or  electro-negative  than  themselves.  Towards  0 
ions  they  may  present  one,  three,  five,  or  even  seven 
valencies  or  poles  of  attraction,  according  to  the 
circumstances  under  which  they  combine.  Sulphur 
is  similar  to  them.  It  is  a  divalent  ion  or  dyad 
towards  electro-positive  ions,  but  a  tetrad  or  even 
hexad  in  the  presence  of  electro-negative  ions. 

In  its  electro-negative  character,  therefore,  sulphur 
is  a  dyad.  It  resembles  oxygen  in  its  chemical 
behaviour  and  can  replace  it  in  its  many  compounds. 
Thus  H20  becomes  H2S  or  sulphuretted  hydrogen. 
All  the  compounds  in  which  0  is  replaced  by  S  are 
called  thio-compounds.  They  are  numerous,  and 
include  thio-alcohols,  thio-ethers,  thio-aldehydes, 
and  thio-acids  ;  and  in  each  case  the  oxygen  is  re- 
placed by  sulphur  by  the  action  of  its  ions.  Thus 
C2H60  +  H2S  =  H20  +  C2H6S  or  ethyl-hydrosulphide, 
a  substance  which  causes  the  peculiar  smell  in  the 
urine  after  eating  asparagus  ;  and  CH40  +  H2S  = 
H20  +  CH4S  or  methyl-hydrosulphide,  one  of  the 
intestinal  gases. 

As  a  tetrad  sulphur  can  unite  with  oxygen  by 
two  valencies  forming  SO  or  oxy-sulphine,  a  dyad 
or  divalent  ion.  One  valency  of  this  ion  may  unite 
with  C  and  the  other  with  an  OH  ion,  and  from  such 
a  combination  many  salts  and  compound  ethers  are 
derived. 

As  a  hexad,  sulphur  unites  with  two  atoms  of 


64  THE  THEORY  OF  IONS 

oxygen  to  form  sulphone,  S02.  This  is  a  divalent 
ion  ;  when  each  of  its  free  valencies  is  united  to  a 
carbon  atom  sulphones  are  formed  ;  with  a  carbon 
atom  to  one  valency  and  an  OH  ion  to  the  other  we 
get  sulphonic  acid  ;  with  H  to  one  valency  and  OH 
to  the  other  we  get  sulphurous  acid  ;  and  with  an 
OH  to  each  valency  we  get  sulphuric  acid. 

Sulphonal  is  an  alcohol-derivative  of  sulphone  ; 
when  one  of  its  methyl-radicals  is  displaced  by  an 
ethyl-radical  we  have  trional.  Other  therapeutic 
compounds  are  derived  from  alcohol,  benzene  or 
naphthaline  radicals  by  sulphone  or  sulphonic  acid 
joining  their  free  valencies,  and  hydroxyl  or  OH 
ions  again  come  into  action  in  some  of  these 
replacements. 

Nitrogen,  like  sulphur,  has  a  variable  number  of 
valencies.  It  can  replace  the  carbon  atoms  in  a 
closed  chain.  Among  its  most  important  combina- 
tions are  those  including  oxygen  and  hydrogen. 

Two  atoms  of  N  may  unite  with  two  OH  ions  to 
form  hypo-nitrous  acid,  N202H2.  This  is  capable  of 
forming  salts  and  ethers.  When  joining  to  other 
compounds,  which  have  only  one  free  valency,  it 
splits  into  hydroximide,  NOH,  which  is  a  divalent 
ion.  This  again  may  be  robbed  of  the  H  atom  and 
remain  as  Nitrosyl  or  the  NO  ion.  When  two 
valencies  of  a  carbon  atom  are  available  they  may 
be  seized  by  hydroximide  or  NOH  ions.  Nitrosyl  or 
NO  ions  are  also  capable  of  entering  into  direct  union 
with  the  carbon  atom  in  various  compounds. 

One  nitrogen  atom  may  also  unite  with  an  0  and 
an  OH  ion  to  form  nitrous  acid,  HN02  or  NO -OH. 


NITROGEN  COMPOUNDS  65 

Salts  are  formed  from  this  acid  by  removing  the  H 
of  OH  in  the  usual  way,  e.g.  by  the  alkali  metals. 
The  radical  Nitroysl,  NO,  is  also  formed  by  removing 
the  OH,  and  the  radical  hydroximide  by  removing 
the  0  from  nitrous  acid.  These  radicals  form  many 
organic  compounds,  as  in  the  following  equation, 
where,  however,  the  by-play  of  the  radicals  is  not 
represented. 

C2H60  +  HN02  -  H20  +  C2H5N02. 

That  is  to  say  ethyl-alcohol  plus  nitrous  acid  forms 
ethyl-nitrite  or  sweet  spirit  of  nitre  and  water. 

When  nitrogen  is  pentavalent  it  may  unite  with 
three  atoms  of  oxygen,  one  of  which  is  an  OH,  and 
thereby  form  nitric  acid,  HN03  or  N02-OH.  This 
acid  also  forms  many  salts,  as  many  metals  are  able 
to  replace  the  H  in  the  molecule.  Aromatic  com- 
pounds are  also  able  to  replace  the  H,  and  in  this 
manner  the  nitro-group  assists  in  the  formation  of 
various  essences.  The  carbon  atom  can  also  unite 
with  the  nitro-group,  not  merely  by  replacing  the  H 
in  the  molecule,  but  by  displacing  the  OH. 

As  a  triad,  nitrogen  combines  with  hydrogen  to 
form  Ammonia,  NH3,  which  is  an  exceedingly 
important  body  in  the  organic  world.  Two  or  more 
valencies  of  the  N  in  NH3  come  into  play  when  it  is 
approached  by  an  electro-negative  group,  e.g.  OH, 
Cl,  Br,  I,  acid  radicals,  etc.  Thus  NH3  +  20H  = 
0  +  NH5O  or  ammonium  hydroxide.  This  body, 
however,  has  not  been  isolated,  any  more  than 
ammonium,  N2H8,  which  is  admitted,  on  all  hands 
to  exist,  and  probably  consists  of  two  NH4  or 
ammonium  radicals  joined. 

5 


66  THE  THEORY  OF  IONS 

When  ammonia  is  approached  by  a  hydrocarbon 
radical  we  get  an  amido-compound  : 

NH3  +  CH3  -  H  +  CH5N  or  methylamine. 

If  another  H  is  removed  from  the  ammonia  we  shall 
have  NH2,  which  is  an  ammonia-rest,  the  amido- 
group,  a  monovalent  ion.  Primary,  secondary, 
tertiary,  and  quaternary  compounds  of  this  group 
are  called  Amines,  or  combinations  of  ammonia  with 
hydrocarbons. 

Mono-amines,  primary  ammonia  bases  or  amido- 
bases,  contain  one  molecule  of  NH3  in  which  one  II 
is  replaced  by  an  alcohol-radical,  e.g.  methylamine, 
ethylamine,  propylamine,  and  benzylamine.  In  the 
secondary  bases  two  H  atoms  are  replaced  by  two 
hydrocarbon  radicals  ;  in  tertiary  bases  all  three 
H  atoms  are  replaced  by  hydrocarbon  radicals ;  and 
in  quaternary  bases  the  triad  nitrogen  of  the 
ammonia  turns  into  a  pentad. 

Di-amines  contain  two  molecules  of  ammonia,  in 
which  the  hydrogen  atoms  may  be  similarly  dis- 
placed by  hydrocarbons.  Poly-amines  contain  three 
or  more  ammonia  or  amido-groups,  in  which  the  H 
atoms  of  the  group  have  been  replaced  by  a  similar 
number  of  hydrocarbon  radicals. 

Nitrogen  becomes  a  pentad  when  joined  to  OH 
or  other  electro-negative  ions  if  there  is  an  electro- 
positive ion  at  hand  to  take  up  the  fifth  valency. 
If  there  is  not,  the  ammonia  gives  up  one  of  its  H 
atoms  to  a  hydroxyl  ion  to  form  water,  and  the 
result  is  hydroxyl-amine,  NH30  or  NH2-OH. 

NH30+H20. 


NITROGEN  COMPOUNDS  67 

This  is  a  basic  ion  which  is  capable  of  forming  many 
compounds,  with  alcohols,  phenols,  aldehydes  or 
acids.  It  would  take  us  much  too  far  to  enter  into 
all  these.  It  must  suffice  to  indicate  a  few  of 
ammonia's  compounds  with  acids,  and  especially 
such  as  are  of  biological  or  physiological  importance. 
AMIDO-ACIDS  are  formed  by  an  organic  acid 
radical  attaching  itself  by  its  alkyl-part  to  the 
amido-group.  Thus  we  have — 

1.  Carbamic  acid,  CH3N02,  or  amido-formic  acid 
from  ammonia  and  formic  acid. 

2.  Glycocoll   or   glycocine,    C2H5N02,  or   amido- 
acetic  acid  from  acetic  acid.     Sarcosine,  C3H7N02)  is 
methyl-glycocoll,  formed  by  the  introduction  of  a 
methyl  radical  into  the  amido-group  of  glycocoll. 

3.  Alanine,    C3H7N02,    or    amido-propionic    acid 
from    propionic    acid.       Cy stein    is    formed    from 
alanine  by  the  radical  SH  displacing  one  H  from  the 
carbon. 

4.  Leucine,  C6H13N02,  or  amido-caproic  acid  from 
caproic  acid. 

5.  Aspartic  acid,  C4H7N04,  or  amido-succinic  acid 
from  succinic  acid. 

6.  Glutaminic  acid,  C5H9N04,  or  amido-glutaric 
acid  from  glutaric  acid. 

7.  Tyrosine,  C9H11N03,  may  be  looked   upon  as 
a  combination  of  alanine  and  phenol ;  it  is  hydroxyl- 
phenyl-amido-propionic  acid. 

8.  Taurine,  C2H7NS03,  is  amido-ethane-sulphonic 
acid. 

The  ami  do-acids  are  peculiar  compounds,  and  very 
important  constituents  of  proteins.  It  has  been 
suggested  that  all  proteins  arise  from  aspartic  alde- 

5—2 


68  THE  THEORY  OF  IONS 

hyde,  C4H7N02,  by  condensation.  When  in  a  free 
state  these  acids  have  a  neutral  reaction.  They  can 
form  combinations  with  other  acids,  and  also  by 
their  carboxyl-end  with  bases. 

AMIDES,  Acid-amines,  or  Aminic-acids.  An 
amido-acid  can  form  other  compounds  with  am- 
monia, by  substituting  a  radical  in  place  of  a 
hydroxyl.  The  amides  or  aminic-acids  are  formed 
by  fixing  ammonia  to  an  acid  at  its  carboxyl-end. 
A  molecule  of  water  is  eliminated  by  loss  of  H 
from  ammonia  and  OH  from  the  carboxyl  -group. 
Thus  Formic  acid  and  ammonia  =  Formamide  and 
water  ;  or  Acetic  acid  and  ammonia  =  Acetamide 
and  water.  Carbamic  acid  and  ammonia  =  Urea 
and  water,  thus  : 


CH3N02  +  NH3  =  CH4N20  +  H20 
or  CO-1STH2.OH  +  NH3  .  CO.NH2-NH2  +  H20. 

Carbamic  acid  does  not  exist  in  a  free  state,  and 
unless  it  meets  with  other  bodies  to  form  carbamides 
it  splits  into  C02  and  NH3.  The  acid  may  however 
join  any  base,  alcohol  or  another  amide-group,  by 
displacing  a  hydroxyl  ;  it  thus  forms  a  salt,  an 
ether  or  an  amide.  Urea  or  carbamide  is  so  formed 
as  the  final  decomposition  product  of  the  oxidation 
of  nitrogenous  compounds  such  as  albumin. 

If  aspartic  or  amido-succinic  acid  be  used  the 
ammonia  ion  displaces  one  of  the  hydroxyls,  and 
the  resulting  amide  is  Asparagine.  If  Benzoic  acid 
is  used  we  get  Benzamide  ;  and  by  joining  the  alkyl- 
part  of  this  to  acetic  acid  we  get  Hippuric  acid, 
C9H9N03,  or  Benzamide-acetic  acid,  which  is  looked 
upon  as  benzoyl  and  glycocoll  linked  together. 


NITROGEN  COMPOUNDS  69 

IMIDES.  Indol  and  skatol,  products  of  pancreatic 
digestion,  are  derivatives  of  secondary  ammonia 
bases.  If  two  H  atoms  of  NH3  are  displaced  the 
ammonia-rest  or  NH  is  designated  an  imido-group. 
This  displacement  may  occur  through  the  influence 
of  OH  ions  or  hydrocarbon-radicals.  If  the  amido- 
base  NH2  displaces  one  H  atom  from  a  benzene  ring 
it  forms  amido-benzene  or  Aniline.  If  another  H 
atom  is  displaced  from  the  amido-group  of  aniline 
by  an  ethyl-radical  it  forms  Ethyl-aniline.  This 
may  be  still  further  attacked  by  OH  ions,  thereby 
abstracting  another  H  from  the  benzene-ring  and 
three  H  atoms  from  the  ethyl-end,  to  form 
water  ;  that  which  is  left  will  form  an  interlocked 
molecular  ring,  Indol,  C8H7N ;  Skatol  is  methyl-indol, 
C9H9N. 

Cholin  is  a  decomposition  product  of  lecithin,  in 
the  animal  organism.  It  is  a  derivative  from  a 
quaternary  ammonium  base,  and  is  really  hydroxy- 
ethyl  -  trimethyl  -  ammonium  -  hydroxide.  Now  in 
tetra  -  methyl  -  ammonium  -  hydroxide  four  methyl- 
radicals  are  joined  to  the  ammonium-hydroxide, 
NOH,  thus  4CH3  +  NOH  =  C4H13NO.  If  one  of  these 
methyl-radicals  is  replaced  by  a  hydroxy-ethyl 
radical,  C2H50,  we  have  cholin,  C5H15N02.  If  a 
molecule  of  water  is  split  off  from  cholin  we  have 
Neurin,  C5H13NO.  Both  these  substances  arise  from 
lecithin,  probably  as  a  result  of  hydrolysis  by  the 
action  of  bacterial  enzymes.  By  exposing  cholin 
to  the  action  of  oxidising  agents  such  as  OH  ions, 
it  loses  two  atoms  of  H  and  becomes  muscarine, 
C5H13N02 ;  the  two  H  atoms  abstracted  by  two  OH 
ions  may  form  water  of  crystallisation,  and  muscarine 


70  THE  THEORY  OF  IONS 

is  then  C5H15NO3.  Cholin  may  be  robbed  of  four 
atoms  of  H  by  OH  ions  or  other  oxidising  agents, 
such  as  an  aldehyde  and  an  acid.  The  result  is 
Betaine,  C5HnN02,  a  non-poisonous  substance  found 
in  beetroot,  other  plants,  and  in  mollusca.  Betaine 
is  also  an  amido-acid,  tri-methyl-glycocoll  or  oxy- 
neurin,  and  is  derivable  from  hydroxy-ammonium- 
alcohol.  If  the  carboxyl-group  of  alanine  or  amido- 
propionic  acid  is  displaced  by  sulphonyl  it  forms 
Taurine,  C2H7NS03.  Taurine  and  cholin  occur  in 
the  bile  as  taurocholic  and  glycocholic  acids.  All 
these  are  products  of  catabolic  processes  in  the 
organism. 

The  mode  of  formation  of  all  the  urea  in  the 
organism  is  not  positively  known  ;  but  that  some 
of  it  is  formed  from  ammonia  in  the  liver  is  proved 
beyond  a  doubt,  and  it  is  considered  to  be  formed 
partly  from  ammonium  carbonate  and  partly  from 
carbamic  acid  or  other  amino-acids  (leucin,  glycocoll 
or  asparagine)  or  extractives  (creatin,  creatinine), 
with  carbamic  acid  as  an  intermediate  product. 
Carbamic  acid  is  not  known  in  a  free  state,  but  only 
in  combination  as  salts.  We  have  seen  how  it  may 
arise  from  formic  acid,  CH202,  by  the  NH2  ion  dis- 
placing an  H  atom  and  joining  the  carboxyl,  CH202 
+  NH2  =  H+CH3N02  or  COOH-NH2.  It  may  also 
be  formed  from  carbonic  acid,  CH203,  by  NH2  dis- 
placing a  hydroxyl.  Carbonic  acid  is  dibasic,  and 
may  have  one  or  both  its  hydroxyls  displaced  by  an 
amido-group,  forming  amides  or  aminic  acids. 
When  both  of  the  OH  ions  are  displaced  by  am- 
monia-radicals it  forms  urea. 


NITROGEN  COMPOUNDS  71 

Formic  acid  Carbamic  acid 

1.  CH202          +  NH2  =       CH3N02      +H. 
(H-CO-OH)  (NH2.CO-OH) 

Carbonic  acid  Carbamic  acid 

or      CH203          +NH2=       CH3N02      +OH. 
(OH-CO-OH)  (NH2.CO-OH) 

Carbamic  acid  Urea 

2.  CH3N02        +NH2=        CH4N20      +  OH. 
(NH2.CO-OH)  (NH2.CO.NH2) 

Other  substances  may  be  formed  from  urea  by  still 
further  substitution.  Thus,  if  the  oxygen  of  urea  is 
replaced  by  an  imido-group,  NH,  it  will  form  guani- 
dine,  CH5N3. 

The  xanthin  compounds  are  closely  related  to 
urea.  Many  if  not  all  of  them  actually  arise  from 
the  decomposition  of  nucleo-proteids,  which  are 
combinations  of  nucleic  acid  with  true  proteids. 
The  nucleic  acids  are  not  all  of  the  same  composi- 
tion, although  they  generally  contain  four  atoms  of 
phosphorus.  They  also  yield  different  products, 
but  these  always  include  one  or  more  of  the  purin- 
bases,  which  are  derived  from  purin,  C5H4N4,  and 
the  most  important  of  which  are  the  following  : 

Hypoxanthin  or  oxy-purin,  C5H4N40. 
Xanthin  or  di-oxypurin,  C5H4N402. 
Uric  acid  or  tri-oxypurin,  C5H4N403. 
Adenine  or  amino-purin,  C5H5N5. 
Guanine  or  amino-oxypurin,  C5H5N50. 
Theobromine  or  dimethylxanthin,  C7H8N402. 
Caffeine  or  tri-methylxanthin,  C8H10N4O2. 
Carnine,  C7H8N405. 


72  THE  THEORY  OF  IONS 

Uric  acid  is  the  representative  of  the  class.  Its 
origin  in  the  animal  organism,  like  that  of  urea,  is 
not  settled  beyond  dispute.  The  urinary  purins 
find  their  origin  in  the  decomposition  of  cell  nucleins 
and  the  free  purin  bases  introduced  in  the  food. 
Knieriem*  observed  an  increase  in  the  excretion  of 
uric  acid  after  administering  amino-acids,  e.g. 
leucin,  glycocoll,  aspartic  acid.  Other  authorities 
agree  that  this  may  be  one  mode  of  origin.  Whether 
the  amino-acids  are  decomposed  by  splitting  off  the 
ammonia  is  unknown,  but  is  considered  very  prob- 
able. Minkowski  found  a  large  amount  of  lactic 
acid  in  the  urine  of  birds  after  extirpation  of  the 
liver  ;  and  considered  that,  at  least  in  birds,  the 
uric  acid  is  formed  in  the  liver  from  lactic  acid  and 
ammonia.  Kowchski  and  Salaskinf  also  consider 
they  have  proved  that  to  be  its  origin,  by  administer- 
ing lactate  of  ammonium  to  birds.  Lactic  acid, 
C3H603,  is  hydroxy-acrylic  acid  or  /3-hydroxy-pro- 
pionic  acid.  It  is  one  of  the  products  of  muscular 
activity,  and  may  arise  from  the  decomposition  of 
amino-acids  and  members  of  the  aliphatic  series. 
Uric  acid  is  decomposable  into  urea  and  alloxan. 

When  two  molecules  of  urea  are  united  by  the 
chain  of  an  acid  we  have  a  diure'ide.  Alloxan  is 
such  a  body,  and  is  derived  from  urea  and  mesoxalic 
acid.  But  mesoxalic  acid  only  forms  this  link  by 
losing  three  atoms  of  oxygen  (e.g.  by  OH  ions  acting 
on  it),  whereby  it  becomes  acrylic  acid,  one  of 
the  aliphatic  series,  closely  related  to  propionic 
acid.  Uric  acid  may  therefore  be  regarded  as  com- 

*  Zeit.fiir  Biologie,  xiii. 

t  Zeit.  Jiir  Physiol.-Chem.,  xxxiii. 


EVOLUTION  OF  PROTEIDS  73 

posed  of  two  molecules  of  urea  and  one  of  acrylic 
acid  united  with  loss  of  three  H  atoms  and  a  mole- 
cule of  water.  Xanthin  by  connecting  two  mole- 
cules of  urea  by  an  acrylic  acid  link,  with  loss  of 
hydrogen  and  water.  Hypoxanthin  only  differs 
from  the  latter  in  having  an  atom  of  oxygen  less  ; 
and  adenine  is  the  imide  of  hypoxanthin.  If  two 
methyls  replace  two  hydrogen  atoms  in  the  imido- 
group  of  xanthin  it  is  converted  into  theobromine  ; 
and  if  three  methyls  replace  three  hydrogen  atoms 
of  the  same  group  it  will  form  caffeine. 

The  true  Proteids  or  the  albuminous  substances 
exist  in  a  living  and  a  non-living  form.  Our  know- 
ledge of  the  former,  the  most  important  and  interest- 
ing substances,  is  practically  nil.  They  consist  of 
complex  compound  molecules,  extremely  unstable, 
and  in  a  constant  state  of  change — that  is,  of  being 
constantly  pulled  down  and  rebuilt  by  the  processes 
of  metabolism.  The  complexity  of  such  molecules 
is  seen  from  the  formula  C636H1025N164FeS30181  which 
is  given  as  the  smallest  possible  empirical  formula 
for  haemoglobin.  Under  the  microscope,  living  pro- 
teids  have  been  observed  to  possess  a  reducing  power 
not  shown  by  dead  proteid.  "  This  and  other  con- 
siderations have  led  to  the  hypothesis  that  living 
proteids  partake  more  of  the  character  of  aldehydes, 
while  the  dead  ones  are  ke tonic  in  nature.  Some 
authorities  are  of  opinion  that  proteids  are  formed 
from  ammonia  and  formic  aldehyde,  as  constituents 
of  aspartic  aldehyde,  4CHOH  +  NH3  =  C4H7N02  + 
2H20  ;  and  that  by  polymerisation,  in  the  presence 
of  sulphuretted  hydrogen,  we  arrive  at  one  of  the 
proposed  formulae  for  albumin,  C72H112N18S022. 


74  THE  THEORY  OF  IONS 

Others  consider  that  living  proteids  consist  of  chains 
of  cyanhydrines  connected  with  benzene  nuclei. 
All  this  is,  however,  mere  paper  speculation  with 
but  a  very  slender  basis  of  facts."* 

At  the  moment  of  death  the  proteids  become 
changed  in  character  ;  they  are  more  stable,  and 
capable  of  being  subjected  to  chemical  investiga- 
tion. As  the  result  of  such  research  Fischer,  Sieg- 
fried, Curtius,  and  others,  have  been  able  to  show 
that  the  dead  proteins  consist  of  a  mixture  of  amido- 
or  amino-acids,  and  can  be  broken  down  to  these  by 
hydrolytic  cleavage.  The  amido-acids  are,  as  we 
have  seen,  ammonium  salts  of  the  fatty  acids.  But 
how  these  acids  are  linked  together  to  form  the 
molecule  of  living  proteid,  how  they  are  influenced 
by  the  introduction  or  abstraction  of  H,  OH,  NH2 
and  CH2  or  other  ions,  is  not  exactly  known.  That 
the  proteid  molecules  are  so  influenced  we  know  ; 
changes  are  produced  by  oxidation,  hydration,  and 
dehydration  which  completely  alter  their  character. 

The  proteins  are  formed  exclusively  by  plants,  so 
far  as  we  know.  Chlorophyll,  as  we  have  seen, 
forms  aldehydes  out  of  the  ions  arising  from  the 
cleavage  of  C02  and  water.  Successive  changes 
lead  to  the  formation  of  aspartic  aldehyde  and 
aspartic  acid.  The  latter  is  amido-succinic  acid, 
and  when  ammonia  displaces  one  of  its  hydroxyls  it 
forms  asparagine,  which  is  also  one  of  the  amido-  or 
amino-acids. 

C4H7N04  +  NH3  •  C4H8N203  +  H20. 

Leucine  (C6H13N02)  is  amido-iso-caproic  acid 
formed  by  ammonia  attaching  itself  to  iso-butyl- 

*  Moller,  ibid.,  p.  431. 


EVOLUTION  OF  PROTEIDS  75 

acetic  acid  or  to  normal  caproic  acid ;  and  so  the 
aliphatic  or  fatty-acid  series  comes  into  the  con- 
struction of  the  amino-acids  and  proteins.  The  im- 
portance of  these  amino-acids  in  the  construction  of 
protein  is  evident,  for  asparagine  and  phenyl- 
alanine  occur  in  most  animal  and  vegetable  pro- 
teids  ;  tyrosin  and  prolin  in  all  animal  proteids  ; 
glycocoll  forms  25  percent,  of  elastin  and  1  of  edestin; 
leucinc  forms  10  per  cent,  of  casein,  20  of  serum- 
albumin,  15  of  fibrin,  21  of  elastin,  and  29  of  haemo- 
globin ;  and  glutaminic  acid  forms  30  per  cent,  of 
gliadin,  8  of  egg-albumin,  10  of  casein,  and  8  of 
serum-globulin. 

The  occurrence  of  protein  substances  which  con- 
tain a  carbohydrate  group  has  been  known  for  some 
time.  It  is  always  an  amino-sugar,  and  usually 
glucosamine,  united  to  the  protein  in  a  glucoside-like 
combination.  It  has  also  been  shown  by  Pavy  and 
others  that  true  proteids  yield  a  carbohydrate  on 
hydrolytic  cleavage.  A  small  amount  of  such  carbo- 
hydrate has  been  separated  from  yolk-proteids,  ovo- 
globulin,  serum-globulin,  paraglobulin,  fibrin,  serum- 
albumin,  and  albumin  of  the  Graminacese.  All  pro- 
teids do  not  contain  a  carbohydrate  group,  for  none 
has  been  obtained  from  casein,  myosin,  fibrinogen, 
ovo-vitellin,  and  some  vegetable  proteids.  It  is  also 
at  present  undecided  as  to  whether  the  carbohydrate 
group  positively  belongs  to  the  proteid  molecule  or 
is  to  be  regarded  as  an  impurity.* 

The  albumins  are  very  sparingly  present  in  vege- 
tables, but  globulins  are  very  common.  They  con- 
tain vegetable-myosin,  which  is  believed  to  be  the 

*  Hainmarsfcen's  "Physiological  Chemistry,"  p.  23. 


76  THE  THEORY  OF  IONS 

precursor  of  gluten-fibrin.  The  latter  being  coagu- 
lated forms  gluten,  from  which  again  phyto-albu- 
mose  (gliadin  or  mucedin)  can  be  separated,  leaving 
the  insoluble  gluten-fibrin.  Aleuron  consists  of  an 
accumulation  of  such  globulins  and  albumoses  about 
a  crystal  or  crystals  of  double  phosphate  of  lime  and 
magnesia  ;  it  is  in  fact  a  mixture  of  homologous 
proteins,  beginning  with  hetero-albumose  and  ending 
with  globulins  and  albumin.  An  aleuron  granule 
may  probably  be  correctly  considered  a  very  coarse 
representation  of  the  finer  proteid  molecule  of 
animal  structures. 

The  proteins  of  animal  structures  are  derived  from 
those  of  vegetable  origin.  Being  consumed,  they  are 
broken  down  by  digestion,  that  is,  they  are  depoly- 
merised  and  transformed  from  colloids  to  crystal- 
loids. Having  entered  the  organism  such  crystal- 
loid substances  are  again  polymerised  to  form  col- 
loids such  as  the  globulins  and  albumins  of  the  blood 
and  tissues. 

Proteid-like  substances  have  been  prepared  syn- 
thetically by  Curtius,  Fischer,  Siegfried,  and  others. 
They  have  succeeded  in  linking  together  two  or  more 
amino-acids  ;  e.g.  glycyl-glycyl  and  glycyl-alanin 
anhydride,  which  are  dipeptides  ;  also  polypeptides, 
containing  three  or  four  glycin  molecules  linked  to- 
gether, have  been  formed.  They  are  esters,  but  give 
the  biuret  reaction,  and  are  considered  to  be  the 
beginning  of  a  proteid  synthesis.  Proteoses  and 
peptones  have  not  yet  been  formed  ;  they  are  prob- 
ably mixtures  of  various  proteins. 

The  instability  of  the  molecules  of  living  proteids 
or  biogens,  as  they  are  called  by  Verworn,  is  due  to 


PFLUGER'S  THEORY  77 

the  interaction  of  the  colloidal  material  with  various 
elements,  notably  oxygen.  Under  favourable  con- 
ditions dead  albumin  remains  intact  for  an  indefinite 
time.  But  living  albumin  decomposes  readily  under 
the  influence  of  external  excitement.  The  cause  of 
this  instability  is  due  to  intra-molecular  changes, 
mainly  produced  by  oxygen,  by  which  the  molecule 
undergoes  cleavage  and  new  groups  are  formed. 
Pfliiger  believes  that  the  characteristic  peculiarity  of 
proteids  and  the  real  cause  of  the  instabilty  of  living 
proteids  is  due  to  the  presence  of  a  cyanogen  radical 
in  the  molecule. 

We  have  seen  carbon  and  nitrogen  joined  together 
by  one  or  two  valencies.  They  may  also  be  joined 
together  by  three  valencies,  forming  thereby  cyano- 
gen, CN,  in  which  the  nitrogen  is  a  triad  and  one 
valency  of  the  carbon  remains  free.  They  may  also 
be  joined  together  by  four  valencies,  as  in  iso- 
cyanogen,  in  which  case  the  nitrogen  is  a  pentad 
occupying  the  four  valencies  of  the  carbon  atom  and 
leaving  one  of  its  own  valencies  free. 

When  nascent  hydrogen,  the  H  ion,  is  joined  to  the 
CN  group  it  forms  hydrocyanic  acid,  HCN,  which 
occurs  in  amygdalin  and  other  vegetable  compounds. 
This  acid  will  combine  with  iron,  potassium,  etc. 
The  cyanogen  radical  or  CN  ion  may  also  combine 
with  alcohols  by  displacing  one  atom  of  hydrogen,  as 
in  the  case  of  cyanhydrine,  C3H5NO  or  C2H50-CN. 
The  cyanhydrines  are  regarded  as  important  sub- 
stances in  biological  construction. 

The  cyanogen  radical  may  also  join  in  different 
ways  with  OH  ions.  One  of  these  combinations  is 
cyanic  acid,  CN-OH,  which  forms  salts  with  various 


78  THE  THEORY  OF  IQNS 

bases,  e.g.  ammonium  cyanate.  The  latter  is  iso- 
meric  with  urea  and  can  be  transformed  into  it  by 
intramolecular  changes.  Cyanic  acid  also  combines 
with  alcohols  to  form  ethers  ;  and  with  sulphur  to 
form  thio-cyanic  acid,  various  combinations  of  which 
are  to  be  found  in  the  aromatic  oils,  e.g.  in  mustard. 
It  is  believed  by  Pfliiger  and  others  that  it  is  cyano- 
gen which  gives  to  protoplasm  its  characteristic  vital 
properties.  This  idea  is  supported  by  analogies 
existing  between  the  cyanide  compounds,  especially 
cyanic  acid,  and  living  albumin.  Both  are  fluid 
and  transparent  at  ordinary  temperatures,  and  set 
or  undergo  gelation  at  a  higher  temperature  ;  both 
break  into  NH4  and  C02  in  the  presence  of  water  ; 
both  produce  urea  by  dissociation ;  both  grow  by 
concatenation  of  atoms,  i.e.  by  homogeneous  groups 
of  atoms  joining  together  chain-wise  into  large  mole- 
cules. So  that  cyanogen  and  alcohol  aldehyde,  or 
the  cyanhydrines  formed  from  them,  follow  out  their 
tendency  to  form  polymeria  or  chains  of  radicals ; 
and  the  co-operation  of  oxygen,  and  afterwards  of 
water  and  salts,  to  form  the  self-decomposable  albu- 
min of  living  matter  is  the  belief  of  Pfliiger  and  his 
followers.  The  non-nitrogenous  products  of  dead 
and  living  matter  agree  in  the  main  ;  but  the  nitro- 
genous products  of  dead  and  living  matter  are 
totally  different.  Urea,  uric  acid,  creatine,  guanine, 
etc.,  the  products  of  living  tissues,  all  contain  the 
cyanogen  radical ;  from  which  it  is  inferred  that 
living  albumin  always  contains  the  cyanogen 
radical,  but  dead  albumin  does  not.  Therefore  the 
cyanogen  radical  is  believed  to  be  the  real  cause  of 
the  instability  of  living  substance.  Max  Verworn 


PFLUGER'S  THEORY  79 

attributes  a  great  value  to  the  cyanogen  theory,  and 
agrees  that  all  the  decomposition  products  of  living 
albumin  contain  the  cyanogen  radical  ;  and  that 
some  of  them,  e.g.  urea,  can  be  synthetised  from 
cyanogen  compounds.  He  says  in  his  "  General 
Physiology  "  :  "I  would  say  that  the  first  albumin  to 
be  formed  was  living  matter,  endued  with  the  pro- 
perty in  all  its  radicals  of  attracting  homogeneous 
parts  with  great  force  and  preference,  in  order  to 
build  them  chemically  into  molecules,  and  so  grow 
indefinitely.  On  this  view  living  albumin  would  not 
have  a  constant  molecular  weight,  because  it  is  a 
huge  molecule  in  an  increasing  process  of  formation 
and  decomposition,  probably  acting  upon  ordinary 
chemical  molecules  as  the  sun  does  upon  small 
meteors." 


V.— INFLUENCE  OF  IONS  ON  THE 
OEGANISM 

ALL  living  substances  consist  of  crystalloidal  and 
colloidal  material.  The  colloids  are  compounds 
based  upon  a  nucleus  of  carbon,  "  the  asymmetrical 
carbon  atom,"  which,  from  its  having  four  poles  of 
attraction  or  valencies,  is  eminently  qualified  to 
form  the  inner  skeleton  of  complex  combinations. 

The  crystalloidal  substances  are  well  known  to 
chemistry.  They  obey  the  ordinary  laws  of  the 
science ;  and  their  absorption  and  excretion  by 
living  organisms  is  governed  by  the  laws  of  osmosis 
and  diffusion.  They  are  divisible  into  the  two 
groups  of  electrolytes  and  non-electrolytes  ;  the 
former  consisting  of  the  salts,  acids,  and  bases  ;  the 
latter  mostly  of  organic  substances  such  as  sugar 
and  urea.  Their  molecular  weight  is  low,  they  have 
a  great  affinity  for  water,  and  readily  pass  through 
animal  membranes.  They  perform  important  duties 
in  the  organism  by  their  physico-mechanical  and 
physico-chemical  properties.  They  influence  many 
of  the  organic  processes,  impart  a  stimulus  to  various 
functions,  and  take  an  active  share  in  metabolism. 
However,  "it  is  not  the  salts,  but  the  ions  of  the 
salts,  which  are  essential  to  the  organism."*  There 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  16. 

80 


THE  COLLOIDS  81 

exists  no  life  process  that  is  not  accompanied  by 
changes  in  the  crystalloidal  and  colloidal  substances 
of  the  cells  and  tissues.  The  physico-chemical  laws 
which  govern  changes  in  crystalloids  and  colloids 
in  vitro  may  be  taken  in  general  as  governing  the 
changes  which  take  place  in  the  same  substances  in 
living  matter. 

The  biological  significance  of  the  crystalloids  is 
however  not  yet  fully  understood,  and  is  one  of  the 
chief  objects  of  research  in  bio-chemistry.  Experi- 
ment has  shown  that  there  are  physiological  effects 
solely  attributable  to  the  ions.  "  The  vital  pro- 
perty of  the  ions  to  keep  in  solution  the  widely  dis- 
tributed globulins  cannot  be  replaced  by  any  other 
kind  of  dissolved  crystalloid."*  It  is  also  known 
that  differences  in  the  concentration  of  the  ions  are 
the  source  of  differences  in  the  electrical  potential  ;t 
and  the  mineral  constituents  of  the  human  body  are, 
in  the  concentration  in  which  they  are  present, 
almost  completely  dissociated.  This  is  equally  true 
of  metallic  or  alkaloidal  salts  introduced  into  the 
body  for  therapeutical  purposes.  Loeb  was  the 
first  who  recognised  the  importance  of  ions  in  the 
electrical  changes  of  organisms,  and  that  changes 
in  the  ionic  constitution  were  the  causes  of  the 
majority  of  electrical  phenomena  observed  in 
animal  organs.  In  every  dilute  solution  the  salts 
are  almost  completely  dissociated  into  ions,  and 
the  remaining  or  undissociated  molecules  are  neutral 
electrically  ;  therefore  the  effect  of  such  a  solution 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  42. 

f  LOG.  cit. 

6 


82  THE  THEORY  OF  IONS 

must  be  due  to  the  ions.  A  pure  ion  effect  parallels 
the  ionic  concentration,  and  not  the  concentration 
of  the  salt  in  the  solution.  Cations  and  anions  in 
many  instances  antagonise  one  another  ;  and  the 
effect  of  a  salt  upon  various  substances,  e.g.  protein, 
— is  the  sum  of  the  effects  of  different  ions. 

We  are  far  from  a  satisfactory  insight  into  the 
nature  of  the  effect  of  ions,  which  may  be  chiefly 
electrical  in  character  and  brought  about  by  the 
polarity  of  matter.  Nevertheless  examples  of  such 
ion  effects  are  to  be  found  in  pharmacology  of  the 
iodides,  cocaine  and  other  drugs,  in  the  absorption 
of  water  by  muscle,  in  the  sense  of  taste,  changes 
in  the  state  of  the  proteins,  etc.  In  the  living 
organism  we  have  to  deal  with  complex  mixtures 
of  crystalloids  and  colloids,  between  which  there 
exist  relations  so  intimate  and  varied  that  some  of 
them  are  still  incapable  of  elucidation.  "  Connected 
with  the  uninterrupted  vital  activity  of  the  cell,  the 
anabolism  and  catabolism  of  its  substance,  is  the 
conversion  of  crystalloids  into  colloids,  and  colloids 
into  crystalloids  ;  and  this  at  present  unexplained 
transformation  serves  at  one  time  to  protect  a  sub- 
stance from  oxidation,  as  in  the  conversion  of 
crystalloidal  sugar  into  colloidal  glycogen ;  at 
another  time  it  protects  the  protoplasm  against 
the  poisons  of  its  own  products."*  These  changes 
are  brought  about  by  the  addition  or  abstraction 
of  ions  from  the  molecule,  by  addition  or  subtrac- 
tion of  side-chains,  and  by  intra-molecular  changes 
dependent  upon  the  electrical  condition  of  the 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  43. 


THE  COLLOIDS  83 

elements.  Absorption,  secretion,  growth,  pharma- 
cological and  perhaps  pathological  processes  as  well 
as  immunity,  are  connected  with  such  changes  in 
state,  a  discovery  of  the  nature  of  which  is  the 
raison  d'etre  of  bio-chemistry. 

The  colloidal  constitution  of  living  matter  is  also 
connected  with  the  problems  of  bio-chemistry,  and 
especially  the  electrical  and  chemical  reactions  which 
occur  in  protoplasm.  Colloids  exist  in  two  forms  : 
a  liquid  form  called  by  Graham  the  sols,  and  a  solid 
or  jelly-like  form  or  gels.  The  colloids  consist  of 
proteioidal  and  lipoidal  materials.  They  possess  a 
high  molecular  weight,  they  do  not  pass  through 
animal  membranes,  and  their  osmotic  pressure  is  so 
low  that  they  diffuse  only  with  the  greatest  difficulty. 
Neither  do  they  possess  electrical  conductivity, 
although  they  for  the  most  part  move  through  an 
electric  current  and  have  an  electrical  reaction. 

A  colloid  consists  of  very  fine  particles  of  matter 
in  a  state  of  suspension.  These  particles  vary  in 
number,  size  and  electrical  charge  ;  and,  like  the 
very  minutest  particles  of  atmospheric  dust,  a.ppear 
to  be  unaffected  by  gravity.  They  are,  however, 
rendered  visible  by  illumination  ;  and  they  remain 
suspended  owing  to  the  development  in  them  of  an 
electro-statical  condition  induced  by  friction  of  their 
surfaces  against  each  other  in  their  molecular  move- 
ments. Colloids  may  be  organic  or  inorganic.  An 
illustration  may  throw  some  light  upon  their  con- 
stitution. If  a  clean  metal  plate  is  put  into  water 
it  assumes  a  weak  negative  electric  charge,  while 
the  surrounding  liquid  becomes  electro-positive. 
Traces  of  the  metal  gradually  drop  off  the  plate 

6—2 


84  THE  THEORY  OF  IONS 

into  the  liquid,  and  it  is  these  particles  or  metallic 
ions  in  the  fluid  which  contain  the  positive  electric 
charge.  If  we  imagine  the  metal  plate  to  be 
divided  under  the  water  into  very  fine  particles  of 
metallic  dust,  they  will,  by  virtue  of  their  minute- 
ness and  the  electro-static  condition  induced  in 
them,  remain  suspended  for  an  indefinite  length  of 
time.  Such  is  a  colloidal  solution.  It  is  a  sus- 
pension of  electrically  charged  particles,  each  of 
which  is  an  electrode.  It  is  an  example  of  colloids 
in  general.  The  chief  laws  and  the  differences 
between  colloids  are  all  referable  to  the  number, 
size  and  electrical  charge  of  the  particles.  Although 
such  particles  appear  to  be  unaffected  by  gravity, 
they  are  affected  by  electrical  changes,  and  clumping 
or  precipitation  can  be  produced. 

It  is  to  such  particles  in  particular  that  I  have 
ventured  to  apply  the  name  of  Meres.  They  are 
not  exactly  inert  particles  ;  they  possess  energy, 
part  of  which  is  potential,  and  part  is  already 
kinetic  as  shown  by  their  electrical  charge,  by  their 
chemical  combinations,  and  in  other  ways.  In  col- 
loidal bodies  such  combinations  appear  to  be  always 
between  ions  and  meres,  and  the  influence  exerted 
by  one  upon  the  other  is  among  the  facts  demon- 
strated by  a  study  of  the  chemistry  of  the  colloids  ; 
and  it  is  to  such  combinations  that  many  physio- 
logical processes  are  due. 

The  chemistry  of  the  colloids  is  therefore  exceed- 
ingly important  both  for  biology  and  therapeutics, 
for  "  there  exists  no  life  process  that  is  not  accom- 
panied by  changes  in  the  colloidal  and  crystalloidal 
substances. ' '  Some  of  the  laws  of  general  physiology 


MERES  85 

can  only  be  clearly  understood  through  a  knowledge 
of  these  substances ;  while  the  pharmacological 
action  of  substances  and  the  process  of  immunisation 
will  only  become  enlightened  by  a  clear  apprehension 
of  the  mode  of  action  of  colloid  upon  colloid  and  the 
interaction  of  crystalloid  and  colloid.  The  chem- 
istry of  the  colloids  is  only  in  its  infancy,  but  good 
work  has  been  done  by  Graham,  Butschli,  Pauli, 
Fischer,  Bernstein,  Billitzer,  and  others,  which  has 
done  something  to  disperse  the  mists  by  which  the 
subject  is  obscured. 

Living  cells  consist  of  a  complex  mixture  of  col- 
loids and  crystalloids  whose  relations  are  ever  varied  ; 
and  the  colloids  are  chiefly  proteioidal  and  lipoidal 
substances,  and  the  changes  in  the  structure  of  living 
matter  consist  largely  of  changes  in  the  colloids. 
"  Connected  with  the  uninterrupted  vital  activity  of 
the  cell,  the  anabolism  and  catabolism  of  its  struc- 
ture, is  the  conversion  of  crystalloids  into  colloids 
and  colloids  into  crystalloids,"*  which  is  constantly 
going  on.  The  reaction  of  living  matter  may  there- 
fore be  elucidated  by  a  study  of  the  changes  in  state 
ex  corpore  of  colloids  and  particularly  of  those  called 
proteins. 

Protoplasm  possesses  characteristics  of  both  solid 
and  liquid  substances.  The  ability  to  stand  alone 
agrees  with  the  properties  of  solids,  and  this  is  seen 
in  the  independence  of  cells.  An  argument  for  the 
fluidity  of  protoplasm  is  however  found  in  the  con- 
dition that  chemical  reactions  take  place  in  the  cell 

*  Fault's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  43. 


86  THE  THEORY  OF  IONS 

with  marvellous  rapidity.  Changes  of  shape  and 
the  internal  structure  of  protoplasm  also  have 
analogies  in  the  variations  visible  in  dead  colloids. 
But  that  all  living  substance  is  liquid  meets  with 
greater  difficulties  than  the  assumption  of  a  solid 
state.  Thus,  for  instance,  an  inner  stabile  differen- 
tiation in  a  liquid  is  impossible,  whereas  the  proteins 
are  stabile.  While  every  part  of  an  amoeba  is 
equally  capable  of  the  functions  of  assimilation, 
stimulation  and  movement,  every  element  in  the 
mass  may  become  a  surface  element,  or  conversely. 
Nevertheless  "  there  exist  peculiarities  in  unicellular 
organisms,  and  in  the  individual  cells  of  higher 
animals,  which  can  scarcely  be  interpreted  otherwise 
than  as  expressions  of  polarity.*  Under  this  heading 
belong  "  the  fact  that  absorption  and  secretion  take 
place  predominantly  in  certain  directions,  the  de- 
pendence of  muscular  stimulation  upon  the  angle  of 
the  current  and  the  direction  of  the  muscular  fibril, 
and  the  polarity  of  the  phenomena  of  degeneration 
in  plants  and  animals.  These  phenomena  indicate 
a  persistent  inner  differentiation  which  can  scarcely 
be  explained  without  the  assumption  of  a  solid 
orientation  of  the  particles  of  living  matter,  "f 
Pauli  considers  that  many  of  the  phenomena  of 
living  tissues  are  to  be  understood  through  a  study 
of  the  non-living  colloids.  The  gels  or  solid  colloids 
such  as  agar-agar  and  gelatine  show  some  of  the 
characteristics  of  living  tissues.  Such  a  jelly  does 
not  take  up  any  other  colloid  brought  into  contact 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  29. 

t  Loc.  cit. 


CONSTITUTION  OF  LIVING  MATTER     87 

with  it,  which  is  comparable  with  the  differentiation 
of  cells.  A  foreign  colloid  may  be  thrust  into  it,  but 
it  shows  no  tendency  to  diffuse,  just  as  in  intra- 
cellular  structures.  Delicately  shaded  changes  in 
state  are  to  be  observed  in  these  colloids,  just  as  in 
living  matter,  through  the  action  of  substances 
within  them.  Thus,  they  become  more  solid  or  more 
fluid,  without  change  in  their  bulk,  by  the  action  of 
crystalloids  or  enzymes  ;  the  latter  producing  partial 
or  complete  peptonisation.  They  also  manifest  the 
phenomena  of  adsorption  and  a  great  degree  of 
selection  with  regard  to  the  substances  absorbed. 
Living  colloids  are  such  as  can  take  up  substances 
soluble  in  water  or  in  ether.  The  latter  are  called 
lipoids,  e.g.  cholesterin  and  lecithin.  It  is  not  known 
how  these  lipoids  are  held  by  the  protoplasm  ;  but 
it  is  probably  governed  by  some  property  of  their 
own,  such  as  solution  affinity.  According  to  Over- 
ton  the  ability  of  many  substances  insoluble  in  water 
to  enter  the  cells  is  entirely  due  to  their  solubility  in 
the  lipoids  of  the  protoplasm  ;  other  substances  also 
enter  the  cells  more  readily,  because  of  their  solu- 
bility in  the  lipoids,  than  their  near  relations  which 
are  soluble  in  water.  The  effects  of  narcotics,  for 
instance,  depend  upon  the  distribution  coefficient, 
that  is  upon  the  rapidity  and  ease  of  their  distribu- 
tion between  two  media,  such  as  the  blood-plasma 
and  the  cell-contents.  The  absorption  of  substances 
insoluble  in  water  from  the  intestine  belongs  to  the 
same  heading.  The  similarity  between  the  physico- 
chemical  properties  of  non-living  gels  and  those 
in  living  matter  is  therefore  extensive,  and  this 
renders  them  suitable  for  an  investigation  into  the 


88  THE  THEORY  OF  IONS 

colloids  of  the  living  body  and  the  action  of  crystal- 
loids upon  them.  The  gels  in  living  organisms  are 
proteins. 

The  sols  or  liquid  colloids  play  an  important  part 
in  the  biological  processes.  Plants  are  able  to  derive 
nourishment  from  absolutely  pure  crystalloidal 
solutions.  In  contrast  to  them,  animals  are  depen- 
dent upon  liquid  colloidal  food.  The  process  of 
digestion  serves  to  prepare  such  nutrient  sols  for 
absorption,  and  being  absorbed  they  are  mechani- 
cally moved  about  and  distributed  through  the 
organism  to  the  nourishing  fluids.  The  globulins 
are  such  sols  :  they  are  colloids  held  in  solution  by 
the  interaction  of  the  colloid  and  a  crystalloid.  The 
sols  possess  properties  common  to  all  suspensions  of 
very  fine  particles.  The  enormous  surface  tension 
or  free  surface-energy  of  these  particles  and  their 
osmotic  pressure  bear  a  relationship  to  each  other  in 
the  cell  which  is  reciprocal.  The  enzymes  also  have 
a  colloidal  constitution  ;  and  Bredig  explains  their 
effects  by  the  enormous  surface  tension  of  the  par- 
ticles. Such  ferment-like  action  is  possessed  even 
by  the  metallic  surfaces  of  the  particles  in  an  in- 
organic colloidal  solution.*  The  metabolic  changes 
for  ever  going  on  in  the  living  organism  compel  us 
to  study  them  as  a  dynamic  process  ;  and  to  find  the 
right  connexion  between  metabolic  physiology  and 
physical  chemistry  is  an  important  problem. 

The  laws  of  colloidal  chemistry  govern  the  changes 
that  go  on  in  living  cells  ;  and,  although  these  laws 
may  be  modified  by  metabolism,  the  parallelism 

*  Pauli's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  34. 


THE  ACTION  OP  IONS  ON  COLLOIDS     89 

between  the  changes  which  go  on  in  colloids  outside 
the  body  and  the  changes  that  go  on  inside  the  body 
is  a  condition  which  cannot  be  denied.  Many  of 
such  changes  are  brought  about  by  the  interaction 
of  ions  of  substances  upon  the  meres  or  particles  of 
the  colloidal  bodies.  The  reactions  observable 
between  ions  and  proteins  (the  chief  colloidal  sub- 
stances of  living  organisms)  become  therefore  of 
importance  in  the  investigations  of  bio-chemistry.  A 
glance  at  some  of  the  results  obtained  by  Pauli, 
Hoffmeister  and  others,  as  given  in  Pauli 's  admirable 
work  called  "  Physical  Chemistry  in  the  Service  of 
Medicine,"  may  therefore  be  useful. 

All  crystalloids  modify  the  gelation  of  colloids,  but 
only  the  electrolytes  or  ionisable  substances  have  the 
power  of  precipitating  them.  The  non-electrolytes 
have  no  power  to  precipitate  them  in  any  concen- 
tration ;  but  they  can  influence  the  property  of  gela- 
tion just  as  the  electrolytes  and  they  act  in  both 
directions  :  urea  inhibits  while  sugar  favours  gela- 
tion. 

The  precipitating  power  of  the  electrolytes  also 
varies.  A  table  given  by  Pauli*  shows  that  the 
cations  Mg,  NH4,  K,  Na  and  Li  increase  in  power  of 
precipitation  in  the  order  given  ;  but  the  anions — 
sulphate,  phosphate,  citrate,  tartrate,  chloride, 
bromide,  iodide  and  sulphocyanate — inhibit  the 
action  of  the  metallic  ions,  and  the  power  to  prevent 
the  precipitation  of  proteins  also  increases  in  the  order 
given.  Thus  the  sulphates  increase  in  precipitating 
power  from  Mg  to  Li  ;  and,  on  the  other  hand,  the 

*  Pauli's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  73. 


90  THE  THEORY  OF  IONS 

sodium  salts  decrease  in  precipitating  power  from 
sulphate  to  sulphocyanate  in  the  order  given.  It 
is  therefore  the  metallic  ion  which  precipitates,  while 
the  anion  inhibits  or  prevents  that  action,  the  ions 
being  antagonistic.  Sodium  acetate  will  precipitate 
protein  because  the  Na  ion  is  too  powerful  to  be 
inhibited  by  the  acid  ion  ;  but  ammonium  acetate 
will  not  precipitate  because  the  acid  ion  is  more 
powerful  than  the  metallic  ion. 

The  effect  of  the  salt  is  therefore  made  up  of  two 
parts,  a  cation  and  an  anion  effect,  and  the  result 
is  the  algebraical  sum  of  the  effect  of  the  ions. 
While  bringing  about  a  physical  change  in  the  state 
of  the  colloid  the  ions  antagonise  one  another  ;  one 
ion  has  a  precipitant,  the  other  a  solvent  effect,  and 
according  as  one  or  the  other  predominates  the 
colloid  is  either  precipitated  or  dissolved  (or  remains 
in  solution)  ;  and  this  is  called  an  additive  ion-effect.* 
It  is  the  protein  constituent  of  protoplasm  which 
constitutes  the  chief  point  of  attack,  or  which  is 
most  readily  affected  by  ions  in  the  organism.  It 
is  well  known  that,  in  a  living  organism,  the  salts 
are  held  fast  and  with  great  force  ;  and  this  affinity 
is  an  analogue  of  the  affinity  exhibited  between  the 
salts  and  the  proteins.  There  can  be  little  doubt 
that  ion-protein  compounds  are  ever  present  in  the 
animal  organism  ;  in  fact,  Pauli  states  that  there  is 
reason  to  believe  that  all  the  protein  constituents  of 
the  protoplasm  enter  into  the  composition  of  this 
substance  only  in  combination  with  ions.f  The 
additive  ion  effects  of  the  salts  show  a  dependence 
upon  certain  quantitative  relations.  This  may  be 

*  Loc.  cit  t  Ibid->  P-  14- 


IONS,  NOT  THE  SALTS,  OF  IMPORTANCE     91 

due  to  the  affinity  between  the  salt  and  the  protein, 
and  is  of  such  "  a  character  that  the  metallic  ion 
and  the  acid  ion  of  a  salt  may  unite  with  different 
asymmetric  parts  of  the  protein  molecule."*  Thus 
the  solubility  of  egg-globulin  depends  upon  the 
presence  of  ionisable  compounds,  for  egg-globulin 
is  precipitated  by  solutions  which  do  not  ionise  as 
sugar  and  urea,  just  as  they  are  by  non-ionised 
water.  All  the  globulins  are  kept  in  solution  by 
such  combinations.  These  facts  throw  a  new  light 
upon  the  importance  of  the  mineral  constituents  of 
the  organism.  "  The  ion-protein  compounds  are  of 
importance  in  the  animal  body  through  their  ability 
to  decrease  the  sensitiveness  to  change,"  especially 
to  changes  in  concentration,  alkalinity,  and  tempera- 
ture, t 

When  proteins  are  subjected  to  heat  they  undergo 
a  change  in  state  called  coagulation.  The  degree  of 
temperature  at  which  this  change  takes  place  is 
known  as  the  coagulation-point.  It  has  been  shown 
by  Pauli  and  others  that  various  salts  have  the 
effect  of  raising  or  lowering  this  coagulation-point, 
and  that  the  effect  is  due  to  the  combination  of  ions 
of  neutral  salts  with  the  colloid. 

Colloids  unite  with  water  and  with  salt  in  about 
the  same  way  ;  and  the  presence  of  water  and  salt 
in  an  organism  mutually  affect  each  other.  If  a 
swollen  colloid — that  is,  one  which  has  taken  up 
water — is  submitted  to  dry  air  it  will  lose  water  ; 
but  there  is  the  greatest  difficulty  in  removing  the 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  13.' 

t  Ibid.,  p.  14. 


92  THE  THEORY  OF  IONS 

whole  of  the  water.  In  like  manner,  the  salt  may 
be  removed  from  a  protein-salt  mixture  by  dialysis, 
but  all  the  salt  cannot  be  removed  ;  the  protein-ion 
combination  is  therefore  very  stable.  This  again  is 
of  importance  in  the  living  organism.  Through  the 
decomposition  of  large  molecules  of  protein  or  carbo- 
hydrate during  metabolism,  there  are  produced  cer- 
tain substances,  e.g.  urea,  sugar,  etc.,  which  are 
of  a  low  molecular  weight,  readily  diffuse,  and  have 
other  characteristics  in  common  with  the  electro- 
lytes. But  fortunately  such  substances  are  non- 
electrolytes,  they  are  only  ionised  very  slightly  or 
not  at  all,  and  they  have  no  power  to  displace  the 
electrolytes  from  the  ion-protein  combination.  The 
ions,  and  not  the  salts,  are  therefore  essential  to  the 
organism,  and  the  stability  of  the  ion-protein  com- 
pounds has  a  protective  influence  upon  its  well-being. 

That  it  is  the  combination  of  ions  with  the  protein 
which  gives  an  electrical  reaction  ;  and  that  it  is 
the  metallic  ion  which  has  the  power  of  precipitating 
protein  has  been  proved  by  experiment. 

When  protein  has  been  rendered  as  free  as  possible 
from  salts  by  dialysis  against  running  water,  thereby 
rendering  it  practically  ion-free,  it  is  found  to  have 
no  electrical  charge  whatever.  But  native  protein, 
i.e.  protein  of  living  organisms,  has  a  recognisable 
negative  electric  charge.  When  positively  charged 
metallic  ions  (cations)  are  added  to  such  a  protein 
they  cause  precipitation  by  neutralising  its  electrical 
charge — that  is,  by  converting  its  kinetic  into 
potential  energy,  so  that  aggregates  of  sufficient 
size  are  formed  to  fall  to  the  bottom. 

If  an  electric  current  is  sent  through  a  solution  of 


IONS  GIVE  THE  ELECTRICAL  CHARGE     93 

electrolytes  (crystalloids)  the  substance  dissociates 
into  ions  which  wander  to  the  positive  or  negative 
pole  as  they  are  negatively  or  positively  charged. 
But  if  a  similar  current  is  sent  through  a  colloidal 
solution  the,  particles  all  move  in  one  direction  and 
accumulate  upon  the  positive  or  negative  electrode 
according  to  the  charge  they  have.  This  is  con- 
clusive that  such  particles  have  an  electric  charge. 
The  native  protein  has  a  negative  charge,  and  its 
particles  collect  about  the  cations  or  metallic  ions, 
which  are  miniature  positive  electrodes,  and  they 
accumulate  thereon  until  aggregates  of  sufficient 
size  are  produced  to  cause  precipitation. 

It  has  been  shown,  by  Biltz  and  others,  that  there 
is  further  a  connexion  between  the  electrical  charge 
and  the  precipitation.  Oppositely  charged  colloids 
mutually  precipitate  each  other,  and  such  precipi- 
tated colloid  has  no  electrical  charge,  i.e.  it  does 
not  move  with  the  electric  current.  Pauli  and  Hoff- 
meister  demonstrated  that  the  electrical  charge 
possessed  by  proteins  is  entirely  due  to  their  associa- 
tion with  ions.  Hardy  and  Bredig  endeavoured  to 
show  that  the  electrical  phenomena  of  colloidal  par- 
ticles were  dependent  upon  an  antagonism  between 
the  surface  tension  and  the  electrical  charge  of  the 
colloidal  particles.  But  Billitzer  does  not  consider 
that  surface  tension  plays  the  part  attributed  to  it 
by  the  former.  If  oppositely  charged  ions  are  added 
to  a  colloid,  the  colloidal  particles  collect  about 
those  ions  through  electro-static  attraction,  the  ions 
acting  as  electrodes,  and  aggregates  are  formed 
which  are  precipitated  or  go  into  solution  according 
to  the  nature  of  the  ion.  Pauli  performed  a  number 


94  THE  THEORY  OF  IONS 

of  experiments  which  show  that  the  conductivity  of 
protein  through  the  presence  of  ions  is  very  great  ; 
and  that  the  electrical  charge  is  entirely  due  to  the 
associated  ion.  In  these  experiments  he  tested  the 
behaviour  of  dissolved  proteins  with  many  salts, 
and  the  results  are  summarised  as  follows  :* 

1.  Protein  which  has  been  carefully  freed  from 
electrolytes  shows  no  electrical  charge. 

2.  None  of  the  albuminous  constituents  of  blood 
serum  show  any  electric  charge  in  the  absence  of 
electrolytes. 

3.  Neutral  salts  of  alkalies  or  alkaline  earths  do 
not  impart  an  electrical  charge  to  uncharged  pro- 
tein. 

4.  A  trace  of  acid  imparts  a  positive  electrical 
charge  through  the  positive  H  ions,  and  alkalies  a 
negative  charge  through  the  OH  ions. 

5.  Alkaline  salts  (e.g.  carbonates  and  phosphates 
of  alkali  metals)   render  protein  electro-negative  ; 
acid  salts  give  a  positive  charge. 

The  native  proteins  of  the  blood  and  tissues 
carry  a  negative  electrical  charge  which  is  derived 
from  OH  ions  split  off  from  the  salts  of  the  serum 
and  lymph. f  When  bicarbonate  of  sodium  is  added 
to  fresh  non-charged  protein  it  assumes  a  strong 
negative  electric  charge  and  becomes  sodium- 
bicarbonate-protein  . 

As  the  electrical  conditions  of  the  proteins  of  the 
body  are  determined  through  the  salts  of  the  fluids, 
so  are  those  of  the  cells  ;  which  again  shows  how  im- 

*  Pauli's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  143. 

t  Loc.  cit.,  p.  145. 


VARIABILITY  OF  THAT  CHARGE        95 

portant  is  a  proper  balance  of  the  salts  in  the 
organism.  Hober  has  found  by  experiment  that  the 
red  blood  corpuscles,  under  normal  conditions,  are 
negatively  charged  ;  but  that  they  are  susceptible 
to  changes  which  depend  upon  variations  in  the  en- 
vironment, especially  changes  in  the  ionic  constitu- 
tion and  concentration.  For  example,  in  an  iso- 
tonic  sugar-sodium-chloride  mixture  the  red  blood 
corpuscles  become  electro-positive  under  the  influ- 
ence of  C02,  and  regain  their  normal  reaction  when 
the  CO o  is  withdrawn.*  The  inference  is  that  red 
blood  corpuscles  suffer  a  complete  change  in  their 
electrical  reaction  during  their  passage  through  the 
pulmonary  circulation.  Many  other  cells  likewise 
show  this  variability  in  electrical  reaction.  Accord- 
ing to  modern  investigations  the  fluids  of  the  body 
are  neutral ;  the  free  H  and  OH  ions  exist  in  them  in 
the  same  proportion  as  in  the  molecule  of  water. 
How  then  is  the  variability  in  the  reaction  of  cells 
to  be  explained  ?  Why  for  instance  do  the  red 
blood  cells  change  their  reaction  when  their  environ- 
ment is  changed  ?  or  why  does  a  protein  assume  a 
positive  electrical  charge  when  it  is  exposed  to  the 
presence  of  an  equal  number  of  H  and  Cl  ions  ?  It 
is  because  the  colloid  is  semi-permeable  to  ions  ;  the 
protein  takes  up  more  H  than  Cl  ions  ;  and  the  same 
liolds  good  for  OH  ions  when  it  is  submitted  to  the 
influence  of  alkalies.  The  red  blood  corpuscle 
becomes  positive  when  exposed  to  the  presence  of 
CO 2  because  it  is  permeable  for  some  of  the  negative 
0  ions  which  it  contains  and  which  leave  it,  whereby 
an  excess  of  the  positive  ions  remains. 

*  Loc.  cit.,  p.  150. 


96  THE  THEORY  OF  IONS 

Ostwald  was  the  first  to  discover,  in  this  semi- 
permeability  for  ions,  the  cause  of  the  electrical 
phenomena  observed  in  cells.  Pauli  admits  it  as  a 
very  probable  explanation ;  and  Bernstein  has 
applied  the  same  idea  to  muscle  and  nerve.  "  If 
we  imagine  the  surface  of  the  muscle  fibril  to  be 
more  permeable  for  positive  ions  than  for  the  nega- 
tive ions  contained  within  the  muscle,  then  the 
muscle  must  carry  a  positive  charge  externally  and 
a  negative  charge  within."  Stimulation  of  the  nerve 
brings  about  the  well-known  phenomena  of  negative 
variation  by  altering  the  permeability  for  ions  ;  and 
Bernstein's  experiments  have  shown  that  the 
muscle  current  follows  very  accurately  the  laws 
governing  ionic  concentration  chains.  "  The  current 
of  rest  is  due  to  the  semi-permeability  of  the  mem- 
branes for  ions  ;  and  when  the  permeability  of  the 
membrane  is  altered  through  some  agency  which  pre- 
cipitates protein  or  causes  it  to  go  into  solution,  we 
get  variations  in  the  current  of  rest."* 

The  two  chief  laws  of  protein  precipitation  hold 
good  for  the  physiological  effects  of  ions.  We  have 
seen  that  protein  forms  the  point  of  attack  of  many 
salts  in  the  organism,  and  that  by  them  a  change  in 
state  is  produced.  This  change  of  state  consists  of 
precipitation  or  solution,  and  frequently  a  coincident 
alteration  in  the  state  of  the  energy  associated  with 
the  molecule.  In  the  case  of  salts  of  the  alkali 
metals  and  magnesium  precipitation  does  not  occur 
until  a  fairly  high  concentration  has  been  reached  ; 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine,' 
p.  150. 


PHYSIOLOGICAL  EFFECT  OF  IONS      97 

and  the  precipitate  redissolves  when  the  mixture  is 
diluted.  In  other  words,  the  action  is  reversible. 
Certain  laws  govern  these  reactions.  As  already 
shown,  the  effect  of  the  salt  is  the  algebraical  sum  of 
the  effects  of  its  individual  ions.  Anions  and  cations 
antagonise  one  another  ;  cations  precipitate,  anions 
inhibit  the  precipitation  *  in  proportion  to  their 
power. 

All  cations  have  certain  physiological  characters 
in  common.  They  precipitate  protein.  They  more 
or  less  increase  the  irritability  of  muscle  and  nerve  ; 
they  excite  intestinal  activity  and  increase  the  blood 
pressure. 

The  anions  have  a  solvent  action  on  protein,  or, 
to  speak  more  correctly,  they  inhibit  the  action  of 
cations  in  general.  The  physiological  effect  of  the 
anions  and  their  solvent  action  upon  proteins  in- 
creases through  the  scale,  from  sulphate  to  sulpho- 
cyanate.  The  sulphates,  citrates  and  tartrates  are 
protein-precipitators,  because  the  anion  is  associated 
with  the  over-balancing  properties  of  the  metallic 
ions ;  they  are  therefore  cathartics.  But  in  the 
nitrates,  bromides,  iodides  and  sulphocyanates  the 
anion  has  the  predominating  influence,  the  charac- 
teristic effect  of  which  is  sedative  attended  by  a 
decrease  of  blood  pressure. 

The  ions  of  salts  of  the  alkaline  earths  and  the 
heavy  metals  have  likewise  been  studied,  and  have 
been  shown  to  obey  the  above  broad  general  rule, 
although  their  action  is  attended  by  complicating 
circumstances. 

It  has  long  been  recognised  that  there  was  a  certain 

*  Brit.  Med.  Jour.,  1896,  ii.,  837. 

7 


98  THE  THEORY  OF  IONS 

relation  between  the  cathartic  effect  of  a  salt  and 
the  metallic  portion  of  it.  It  is  now  known  that 
their  effect  in  producing  catharsis  and  diuresis  is  due 
in  part  to  the  increased  blood  pressure  they  cause 
and  in  part  to  their  action  upon  the  protein.  The 
cathartic  and  precipitating  power  parallel  one 
another  in  all  of  them.  The  heavy  metals  cause 
precipitation  in  any  concentration. 

The  sulphocyanates  are  the  last  of  the  anion 
series,  and  possess  the  properties  of  the  group  in  the 
highest  degree.  The  Br  ion  has  a  well-marked 
sedative  effect ;  the  I  ion  has  a  multiplicity  of 
effects  such  as  lowering  of  blood  pressure,  influencing 
the  metabolism  of  the  thyroid  gland,  and  the  resolu- 
tion of  various  inflammatory  exudative  products. 
Williamson  has  shown  that  under  the  influence  of 
potassium  iodide  changes  occur  in  the  structure  of 
leucocytes  ;  in  the  small  oxyphile  leucocytes  the 
granules  become  gradually  less  distinct,  and  eventu- 
ally the  protoplasm  appears  perfectly  homogeneous 
and  stains  with  eosin  very  feebly  ;  the  larger  eosino- 
phile  cells  show  no  change  whatever.*  This  effect 
was  also  observed  under  the  influence  of  pilocarpin 
nitrate,  sodium  salicylate,  carbolic  acid,  turpentine 
and  camphor. 

The  sulphocyanates  have  been  specially  studied  by 
Pauli  and  Bruylants.  The  latter  showed  that  there  is 
a  relationship  between  the  metabolism  of  the  sulpho- 
cyanates and  the  purin-bodies.  Edinger  has 
shown  that  iodine  and  sulphocyanates  exist  in  the 
same  places  in  the  organism ;  and  that  sulpho- 
cyanates do  not  pass  through  the  body  even  in  the 

*  Brit.  Med.  Jour.,  1896,  ii.,  837. 


THE  HEAVY  METALS  99 

smallest  doses  without  influencing  metabolism.  The 
excretion  of  sulphocyanate  is  decreased  when  iodine 
is  taken,  and  is  completely  stopped  when  iodine  is 
produced ;  under  such  circumstances  no  sulpho- 
cyanate is  found  in  the  saliva. 

Another  factor  is  the  relation  between  the 
effects  of  iodides  or  sulphocyanates  and  the 
effects  of  salts  of  the  heavy  metals  or  alkaline 
earths.  "  It  has  been  definitely  established  through 
exact  observation  and  experiment,  that  the 
iodides  favour  and  bring  about  the  excretion  of 
ions  of  the  heavy  metals,  e.g.  lead  and  mercury,  in 
cases  of  chronic  intoxication.  The  explanation  of 
this  fact  which  has  long  been  known  therapeutically, 
has  been  sought  in  the  formation  of  soluble  albu- 
minates  which  the  iodides  have  been  supposed  to 
bring  about."*  In  fact,  the  iodides  not  only  inhibit 
the  precipitation  of  protein  by  the  metallic  ion,  but 
they  dissolve  already  existing  precipitates. 

The  heavy  metals  Pb,  Zn,  Hg,  etc.,  coagulate 
proteins  even  in  the  weakest  concentration.  There 
is  at  first  a  rapid  increase  in  the  power  of  precipita- 
tion with  an  increase  in  the  concentration,  but  this 
falls  to  zero  as  concentration  goes  on.  Still  further 
concentration  will  cause  a  second  precipitate,  which 
is  very  heavy  and  again  soluble.  But  the  precipi- 
tating power  of  these  metals  suffers  a  great  change 
in  presence  of  the  anions  such  as  iodide  and  sulpho- 
cyanate. "  If  the  ions  of  the  metal  are  present  in 
a  low  concentration  the  precipitation  of  protein  is 
prevented  altogether ;  if  present  in  larger  amount  the 

*  Pauli's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  84. 

7—2 


100  THE  THEORY  OF  IONS 

protein  precipitation  is  markedly  increased."*  In 
the  case  of  living  animals  only  the  former  possibility, 
that  of  the  presence  of  a  low  concentration  of  ions, 
comes  into  consideration.  The  iodides  and  still 
more  sulphocyanates  "act  under  these  circumstances 
as  substances  which  favour  the  formation  of  readily 
soluble  ion-protein  compounds  through  which  the 
elimination  of  the  heavy  metals  is  greatly  aided,  "f 
The  relationship  between  the  salts  and  esters  was 
studied  by  Pauli  through  the  sulphocyanates. 
Esters  are  combinations  of  an  alcohol  and  an  acid  ; 
they  are  scarcely  dissociable  into  ions  in  aqueous 
solutions,  and  there  is  a  wide  difference  between 
their  power  of  entering  the  cells  of  an  organism  and 
that  of  the  ionisable  salts.  Overton  has  shown  that 
esters  readily  enter  the  cells  because  they  are  soluble 
in  the  lipoids — lecithin,  cerebrin,  cholesterin — of  the 
cells.  Salts  on  the  other  hand  enter  the  protoplasm 
with  difficulty  because  of  its  comparative  impermea- 
bility to  them.  The  ester  enters  the  cell  and  be- 
comes saponified  by  union  with  the  lipoids,  whereby 
the  anion  of  the  acid  is  set  free,  and  a  physiological 
anion  effect  follows.  Pauli  found  for  instance  that 
if  an  experiment  be  made  with  sodium  sulphocyanate 
and  the  amyl-ester  of  sulphocyanic  acid,  a  character- 
istic sulphocyanate  effect  will  follow  in  both  cases, 
but  while  2  or  3  drops  of  the  ester  will  cause  a  fatal 
intoxication  in  an  animal,  from  8  to  10  grains  of  the 
salt  must  be  injected  subcutaneously  to  produce  the 
same  effect.  The  ester  enters  the  cell  readily,  and 
the  anion  is  not  set  free  until  it  is  within  it ;  but  the 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  85.  f  Loc.  cit. 


IONS  AND  LIPOIDS  101 

salt  is  dissociable  into  ions  before  it  reaches  the  cells, 
and  the  protoplasm  is  not  so  permeable  to  the  ions 
as  to  the  ester.  There  are  numerous  drugs  having 
an  ester-like  construction.  Cocaine  is  the  methyl- 
ester  of  benzoyle-ecgonin  ;  eucaine  is  an  ester  ;  the 
orthoforms  and  ansesthesin  are  likewise  esters.  It 
is  the  presence  of  the  alcohol  radical  which  renders 
this  effect  possible  ;  and  the  saponification  of  the 
ester  by  union  with  the  lipoids  of  the  protoplasm 
liberates  the  anion  and  permits  it  to  become  effec- 
tive. Cocaine  is  twenty  times  more  effective  as  an 
anaesthetic  than  benzoyle-ecgonin  ;  nevertheless  the 
latter  is  the  active  principle  of  cocaine  and  is  disso- 
ciated from  it  by  union  with  the  lipoids  of  the  cell. 
"  Existence  in  the  form  of  an  ester  is  a  sine  qua  non 
of  a  useful  local  anaesthetic  whose  active  anions 
must  enter  the  endings  of  the  sensory  nerves."*  A 
consideration  of  the  subject  of  narcosis  was  made  by 
Meyer.  When  a  substance  is  put  into  a  vessel  with 
two  unmixable  fluids  such  as  oil  and  water,  the 
amount  of  the  substance  which  is  dissolved  in  the  oil 
and  in  the  water  was  found  by  him  to  bear  a  definite 
proportion  or  relationship  to  each  other.  This  ob- 
servation led  him  to  form  a  theory  of  narcosis  which 
was  based  upon  the  distribution  of  the  active  sub- 
stance between  the  watery  fluids  of  the  tissues  and 
the  fat-like  constituents  of  the  nerve  cells. 

The  activity  of  metallic  ions  can  also  be  increased 
by  combination  with  an  alcohol-radical  or  trans- 
formation into  an  ester  ;  and  most  acute  metallic 
intoxication  can  be  brought  about  in  animals  by 

*  Pauli's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  95. 


102  THE  THEORY  OF  IONS 

ethylic  compounds  of  lead,  zinc  or  mercury.  Even 
in  therapeutics  advantage  is  sometimes  taken  of 
such  ester-like  combinations. 

There  is  still  another  way  in  which  the  specific 
effects  of  many  ions  can  be  increased  or  decreased, 
viz.  through  the  combination  of  one  ion  with  another. 
This  occurs  when  ions  of  the  alkaline  earths  act  upon 
protein  in  the  presence  of  alkali  metals.  The  pre- 
cipitation of  protein  which  can  be  brought  about  by 
the  alkaline  earths  may  be  inhibited  through  the 
addition  of  alkali  metals,  or  hastened  through  addi- 
tion of  the  anions,  the  most  powerful  of  which  are  the 
sulphocyanates.  Indeed  there  seems  to  be  a  physio- 
logical antagonism  between  the  monovalent  cations 
Na,  K,  NH4,  Li,  and  the  divalent  cations  Ca,  Ba,  Sr, 
etc.  ;  as  well  as  a  synergistic  increased  effect  of  the 
anions  in  the  presence  of  calcium,  barium  and  stron- 
tium. This  physiological  antagonism  has  already 
been  noted  in  Loeb's  experiments  with  ions  upon  the 
development  of  the  eggs  of  Fundulus  magellus,  a 
small  bony  fish,  upon  the  contraction  of  the  swim- 
ming bell  of  medusae  and  upon  ciliary  movement. 
There  is  a  marked  difference  in  the  electrical  charge 
carried  by  the  monovalent  and  divalent  ions,  and 
this  may  be  taken  in  part  as  explanatory  of  the 
antagonism  between  them. 

The  relationship  of  calcium,  barium  and  strontium 
to  the  proteins  is  important,  because  of  the  position 
occupied  by  calcium  in  physiology  and  pathology. 
They  occupy  a  position  between  the  alkali  metals 
and  the  true  heavy  metals.  In  common  with  the 
former  they  have  a  high  precipitating  power  ;  in 
common  with  the  latter  they  form  a  firm  bond 


IONS  AND  LIPOIDS  103 

between  the  ion  and  the  protein.  This  is  important 
because  of  their  affinity  for  the  musculature  of  the 
heart  and  bloodvessels,  and  the  processes  of  calcifi- 
cation, atheroma  and  arterio-sclerosis  which  depend 
upon  such  affinity.  The  firm  union  of  the  ion  and 
protein  takes  place  even  before  the  precipitation 
limit  is  reached.  But  the  precipitating  power  of 
the  metallic  ion  is  markedly  depressed  by  the  anion 
Br,  still  more  by  I,  and  most  of  all  by  the  sulpho- 
cyanate  anion,  which  also  has  a  strong  affinity  for 
the  protein.  A  firm  bond  can  be  formed  by  Ca  even 
in  the  presence  of  iodide  or  sulphocyanate  anions. 
The  calcium-iodide-protein  is  however  much  more 
soluble  than  calcium-carbonate  or  phosphate-pro- 
tein. The  I  ion  not  only  forms  a  soluble  protein- 
calcium  combination,  but  by  its  presence  inhibits 
or  prevents  the  formation  of  insoluble  calcium- 
protein  combinations  and  favours  the  excretion  of 
the  metallic  ion.  This  is  the  basis  for  the  clinical 
observation  that  the  continued  use  of  iodides  is 
useful  in  the  treatment  of  arterio-sclerosis  and  will 
retard  its  course. 

It  has  thus  been  established  by  experiment  and 
clinical  observation  that  the  iodides  and  sulpho- 
cyanates  bring  about  the  excretion  of  lime,  lead  and 
mercury  from  the  human  system  by  forming  ion- 
protein  compounds  which  readily  go  into  solution. 
Therapeutics  may  therefore  continue  to  speak  of 
the  alterative  and  resolvent  effect  of  drugs,  and  is 
presumably  correct  in  speaking  of  such  actions  as  the 
effects  of  ions  upon  the  colloids.  Indeed  the  action 
of  all  salts  is  the  effect  of  its  ions  upon  the  colloids 
or  crystalloids  in  the  organism.  Most  of  the  alka- 


104  THE  THEORY  OF  IONS 

loids  are  also  ionisable  and  have  a  similar  mode  of 
action.  Many  of  the  non-ionisable  therapeutic 
agents,  as  narcotics,  sedatives  and  bactericides,  have, 
through  their  ester-like  structure,  an  intimate  rela- 
tion with  the  lipoids  of  the  cells  and  become  ionised 
by  combining  with  them.  In  this  way  an  anion  is 
liberated  by  which  the  pharmacological  effect  is 
produced.  Just  as  the  non-ionised  compound  finds 
its  selective  point  in  the  lipoids,  so  the  ionised  ones 
find  their  point  of  attack  in  the  proteins,  "  and  a 
difference  in  the  distribution  or  a  replacement  of 
the  normal  ions  of  the  cell  would  be  connected  with 
changes  in  the  state  of  the  colloids  and  consequently 
of  their  functions."* 

The  influence  of  ions  upon  physiological  functions 
such  as  growth,  irritability  and  life  itself,  is  of  im- 
portance not  only  to  the  biologist  but  to  the  patho- 
logist, especially  in  connexion  with  the  subject  of 
disinfection.  The  experiments  of  Loeb  have  been 
already  referred  to  ;  it  was  he  who  first  observed 
that  certain  ions  were  toxic  and  others  antitoxic  to 
living  tissues.  The  fertilised  eggs  of  •  Fundulus 
magellus  develop  equally  well  in  distilled  water  or 
in  sea-water.  If  however  the  eggs  were  put  into 
a  solution  of  NaCl  of  the  same  strength  as  sea-water 
they  all  died  in  a  few  hours.  But  if  a  small  amount 
of  calcium  chloride,  a  constant  constituent  of  sea- 
water,  be  added,  the  development  proceeds  and 
normal  embryos  are  produced.  The  sodium  is  toxic 
and  the  calcium  ion  antitoxic.  This  is  an  instance 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  86. 


EFFECT  OF  IONS  ON  GROWTH        105 

not  only  of  the  toxicity  of  one  of  the  ions,  but  of 
antagonism  between  a  monovalent  and  a  divalent 
metallic  ion.  An  opposite  effect  of  these  ions  upon 
medusae  was  observed  ;  the  bell  continuing  to  con- 
tract in  a  pure  solution  of  NaCl  after  removal  of  the 
nervous  system,  and  ceasing  to  contract  when 
calcium  or  strontium  was  added  ;  again,  however, 
witnessing  to  the  antagonism  between  the  ions. 
Ciliary  action  is  also  stimulated  by  one  and  de- 
pressed by  the  other.  The  excised  gastrocnemius 
of  the  frog  is  stimulated  to  contract  by  pure  sodium 
chloride  solution  and  checked  by  calcium  or  stron- 
tium ;  while,  on  the  other  hand,  pure  solution  of 
sodium  chloride  is  toxic  to  heart  muscle,  and 
calcium  or  strontium  is  antitoxic. 

Extended  observations  of  the  effects  of  ions  on 
heart  tissue  were  made  by  Knight.*  The  experi- 
ments were  upon  the  embryos  of  perch  and  Fundulus. 
The  general  result  of  the  observations  was  that 
chlorides  of  the  metals  depress  the  heart  beat ;  but 
the  degree  of  the  depression  depends  upon  the  kind 
of  metallic  ion.  Heavy  metals  like  Cu  and  Au 
caused  the  beat  of  the  heart  to  fall  gradually  until 
it  ceased  beating,  the  ventricle  ceasing  first.  Lighter 
metals  such  as  K,  Na,  Li,  Cs  were  also  used.  Potas- 
sium and  caesium  chlorides  acted  as  heart  depres- 
sants, the  cation  K  being  more  energetic,  and  the 
auricle  continued  to  beat  a  few  times  after  the 
ventricle  ceased  to  contract.  Calcium  and  strontium 
stimulated  the  contractile  efforts  of  the  heart ;  while 
Mg,  Ba,  Be,  Zn,  and  Cd  acted  as  depressants.  The 
addition  of  calcium  chloride  to  the  solution  always 

*  Brit.  Med.  Jour.,  1897,  ii.,  1484. 


106  THE  THEORY  OF  IONS 

inhibited  the  depressant  effect  of  K  and  Ba.  In 
these  observations  we  see  the  effect  of  cation  and 
anion.  The  positive  electrical  charge  of  the  metallic 
ion  counterbalances  the  negative  electrical  charge 
of  the  native  protein.  Many  of  the  cations  increase 
the  irritability  of  both  muscle  and  nerve.  The  ions 
of  Ba,  Ca,  and  Sr  stand  between  the  alkali  metals 
and  the  heavy  metals  as  regards  protein  precipita- 
tion, but  they  stimulate  irritability.  The  anion 
effect  is  seen  in  the  depression  which  follows  the 
ions  of  the  halogen  compounds,  unless  it  is  over- 
balanced by  the  metallic  ion. 

Experiments  showing  the  influence  of  ions  upon 
growth  were  made  by  Moore,  Roaf  and  Whitley  on 
the  tadpole  of  Rana  temporaries  and  other  cellular 
structures.*  Living  cells  are  very  susceptible  to  a 
change  in  the  proportion  of  H  and  OH  ions,  both  of 
which  are  toxic  when  the  concentration  exceeds  a 
certain  degree.  The  toxicity  of  acid  salts  is  due  to 
the  H  ion,  of  alkaline  salts  to  the  OH  ion.  An 
increase  of  alkalinity  tends  to  an  increased  cell 
division  or  growth  of  parts ;  but  cell  division  becomes 
irregular  or  ceases  if  the  OH  ions  exceed  a  certain 
concentration.  Acids  and  acid-salts,  on  the  other 
hand,  exhibit  a  retarding  influence  on  growth,  cell 
development  being  arrested.  Neutral  salts  do  not 
show  much  toxicity  ;  they  have  very  little  effect 
until  the  osmotic  pressure  rises  above  that  of  the 
body-fluids  of  the  organism.  When  the  isotonic 
point  is  reached  there  is  a  short  range  at  which 
these  salts  are  toxic,  dependent  upon  the  effects  of 
the  metallic  ion.  Barium  and  ammonium  are  toxic 

*  Brit.  Med.  Jour.,  1906,  ii.,  1788. 


EFFECT  OF  IONS  ON  BACTERIA       107 

before  the  isotonic  point  is  reached.  Ions  of  the 
phosphates  favour  cell  development  when  the  ionic 
concentration  is  low,  but  retard  it  when  the  con- 
centration is  high. 

Upon  micro-organisms  their  influence  was  studied 
by  Kronig  and  Paul*,  who  used  specially  the  spores 
of  anthrax  and  Staphylococcus  pyogenes  aureus  for 
their  experiments.  These  are  of  importance  in  con- 
nexion with  the  subject  of  disinfection,  and  the 
reader  is  referred  to  the  original  paper  for  a  fuller 
account  of  the  observations  of  which  a  mere  outline 
can  be  given  : 

1.  The  ions  of  Hg,  Cu,  Ag,  Zn,  Cd,  Pb,  and  Au, 
are  all  toxic.  They  are  protein  precipitators  even 
in  the  lowest  concentration.  The  observers  found 
that  the  toxic  action  of  salts  of  these  metals  upon 
living  vegetable  cells  stands  in  a  definite  relation  to 
the  electrolytic  dissociation.  The  action  of  the 
metallic  ion  depended  not  only  upon  the  specific 
effect  of  the  cation,  but  upon  the  ionic  concentra- 
tion and  association  with  an  anion.  The  halo- 
gens Cl,  Br  and  I,  have  a  destructive  effect  which 
decreases  as  their  atomic  weight  increases.  Not  only 
the  halogen,  but  the  cyanogen  compounds  of  Hg 
disinfect  in  proportion  to  their  dissociation.  The 
disinfecting  power  of  an  aqueous  solution  of  mer- 
curic chloride  is  diminished  by  addition  of  HC1  or 
another  halogen  compound,  probably  through  the 
recombination  of  ions.  (An  instance  of  the  dissocia- 
tion of  one  substance  into  ions  and  their  recombina- 
tion to  form  another  substance  is  observed  after 
testing  diabetic  urine  with  Fehling's  solution.  If 

*  Zeit.f.  Hyg.  und  Infections!*.,  1897,  xxv.,  112. 


108  THE  THEORY  OF  IONS 

the  contents  of  the  test-tube  are  allowed  to  stand 
for  a  few  days,  the  decolorised  fluid  gradually  regains 
its  blue  colour  from  a  recombination  of  Cu  and  SO4 
ions.)  Neutral  salts  have  an  extremely  feeble  power 
of  destruction  over  the  bacteria.  But  the  disin- 
fecting power  of  nitrate,  sulphate  or  acetate  of  Hg 
in  aqueous  solution  is  increased  by  the  addition  of 
a  halogen  compound.  This  clearly  shows  the  asso- 
ciation between  certain  metallic  ions  and  anions. 

2.  The  acids,  both  inorganic  and  organic,  have  a 
destructive  effect  upon  the  bacteria  which  is  pro- 
portionate to  the  concentration  of  H  ions  in  the 
solution.     Oxidising  agents,  e.g.  nitric,  chloric,  per- 
manganic   acids,    have    their   power   increased    by 
addition  of  a  halogen  acid,  as  HC1  to  permanganic 
acid. 

3.  The  alkaline  salts  of  K,  Na,  Li  and  NH4  in 
solution  were  also  destructive  to  the  bacteria  in 
proportion  to  the  concentration  of  OH  ions.     H  ions 
are  more  destructive  to  anthrax  spores  and  staphy- 
lococcus  than  OH  ions  in  equal  concentrations. 

The  direct  application  of  ions  as  a  therapeutical 
agent  has  been  put  to  practical  use.  In  a  paper 
read  by  Professor  Stephane  Leduc  an  account  was 
given  of  such  a  mode  of  application.  The  facility 
of  introducing  electrolytic  substances  through  the 
skin  or  surface  of  a  wound  increases  the  power  of 
medicine.  The  knowledge  that  the  electric  current 
provokes  an  exchange  of  contents  between  the  con- 
stituents of  two  different  electrolytes  or  between 
two  different  cells  has  been  taken  advantage  of  in 
therapeutics.  Such  an  interchange  can  take  place 
at  the  surface  between  the  skin  and  the  electrodes. 


DIRECT  APPLICATION  OP  IONS       109 

"  As  the  cations  go  down  the  electric  current  and 
the  anions  go  up,  so  under  the  anode  the  cations 
will  penetrate  through  the  skin,  while  the  anions 
will  penetrate  under  the  cathode."*  This  is  a 
regular  effect,  and  by  taking  advantage  of  it  many 
electrolytic  substances  can  be  introduced  through 
the  skin  under  the  impulse  of  the  electric  current. 
The  coagulation  of  plasma  forms  no  obstacle  to  the 
entrance  of  such  ions,  and  their  action  will  be  in 
proportion  to  the  permeability  of  the  proteins  to 
the  ions. 

In  the  direct  ionic  application  the  electrodes  are 
covered  by  fifteen  to  twenty  layers  of-  absorbent  lint 
or  other  tissue  and  well  soaked  in  the  solution  to  be 
ionised.  Fresh  tissue  must  be  used  at  each  sitting. 
The  solution  must  be  made  with  pure  distilled  water, 
otherwise  the  introduction  of  undesired  ions  may 
result.  Iodine  ions  can  be  introduced  into  the 
thorax  by  this  method.  The  solution  of  sodium  or 
potassium  iodide  is  applied  on  absorbent  tissue  to 
the  cathode  and  this  to  the  affected  part,  and  a 
current  of  60  to  100  milliamperes  is  sent  through  it. 
The  ions  have  a  great  speed,  for  they  are  driven  not 
only  by  the  electro-motive  force,  but  by  the  high 
osmotic  pressure  ;  and  in  ten  to  fifteen  minutes 
iodine  appears  in  the  saliva  and  can  be  detected  by 
starch.  The  solution  must  be  applied  by  the 
cathode,  for  if  it  be  applied  at  the  anode  no  iodine 
will  be  found  in  the  saliva,  f  This  mode  of  treatment 
may  be  used  in  thoracic  diseases,  in  ankylosis, 
scoliosis,  old  neuralgias,  and  other  ailments.  Ions  * 

*  Brit.  Med.  Jour.,  1907,  ii.,  631. 
f  Loc.  cit. 


110  THE  THEORY  OF  IONS 

other  than  iodine  can  be  used.  Care  must  be  taken 
in  carrying  out  the  application,  for  a  caustic  effect  is 
apt  to  be  produced.  It  is  necessary  to  use  a  current 
of  strong  intensity  and  density  to  produce  the  thera- 
peutic effect.  "If  the  application  is  defective  the 
proper  intensity  cannot  be  reached,  the  skin  being 
burnt.  This  burning  of  the  skin  is  the  main  obstacle 
to  electro-ionic  medication  ;  but  it  is  in  a  large 
measure  avoidable."*  It  is  caused  by  the  H  and 
OH  ions  produced  at  the  electrodes,  both  of  which 
enter  the  skin  and  are  destructive  to  the  cells  in 
such  a  high  ionic  concentration.  But  with  proper 
precautions  as  to  the  covering  of  the  electrodes, 
their  cleanliness,  and  careful  application  to  the  skin, 
the  caustic  ions  may  be  prevented  from  destroying 
or  even  damaging  its  cells. 

This  treatment  opens  up  a  new  path  in  thera- 
peutics, and  by  following  it  a  new  mode  of  medica- 
tion may  be  devised  for  many  ailments. 

*  Leduc :  loc.  tit. 


VI.— OXIDATION  AND  IMMUNITY 

ACCORDING  to  the  view  which  was  formerly  generally 
accepted,  animal  oxidations  occurred  in  the  fluids 
of  the  organism.  To-day,  led  by  Pfliiger  and  other 
investigators,  we  believe  that  oxidation  occurs  in 
the  tissues,  and  with  formed  elements.  How  oxida- 
tion occurs  is  not  a  settled  point,  but  it  may  be 
viewed  from  the  ionic  standpoint. 

A  body  which  is  oxidised  by  neutral  oxygen  at 
the  temperature  of  that  body  is  said  to  be  easily 
oxidisable  or  auto-oxidisable.  On  the  other  hand, 
bodies  which  are  indifferent  or  nearly  indifferent  to 
neutral  oxygen,  as  the  proteids,  fats,  and  carbo- 
hydrates, are  not  auto-oxidisable,  but  are  said  to  be 
dys-oxidisable  or  brad-oxidisable  substances.  How 
do  such  oxidations  take  place  ?  In  auto-oxidation 
a  cleavage  of  the  neutral  oxygen  into  ions  occurs. 
The  auto-oxidisable  substance  combines  with  one  of 
the  oxygen  ions,  while  the  other  is  free  to  oxidise 
dys-  or  brad-oxidisable  substances  which  may  be 
present  at  the  same  time.  The  latter  is  called  a 
secondary  oxidation. 

Living  protoplasm  has  a  peculiar  construction  de- 
pendent upon  the  special  construction  of  its  proteins. 
These  are  called  living  or  active  proteids  or  biogens  ; 
and  they  differ  from  non-living  proteid,  such  as  is 

111 


112  THE  THEORY  OF  IONS 

seen  in  the  serum  and  tissue  fluids,  in  being  more 
unstable  or  having  a  greater  tendency  to  intra- 
molecular change.  We  have  already  seen  that  this 
instability  is  ascribed  by  Pfliiger  to  the  presence  of 
cyanogen,  and  by  Latham  to  cyanhydrines  in  the 
molecule.  But  it  is  claimed  by  Verworn  that  the 
changes  are  due  to  the  introduction  of  oxygen  into 
the  biogen  molecule,  which  he  considers  has  a  side- 
chain  of  an  aldehyde  character  to  act  as  an  oxygen 
receptor.  Loew  considers  that  instability  to  be 
due  to  the  simultaneous  presence  of  an  aldehyde 
and  amino-acid  groups  in  the  molecule.  He  be- 
lieves that  in  the  living  proteid  they  are  separate, 
and  that  when  they  combine  the  protoplasm  dies  or 
is  changed  into  a  stable,  non-living  proteid. 

The  oxidations  which  occur  in  living  protoplasm 
are  explained  differently.  If  the  protoplasmic  proteid 
is  not  indifferent  to  neutral  oxygen,  there  may  be  a 
cleavage  of  the  oxygen  molecule  whereby  the  living 
proteid  is  oxidised  by  one  of  the  ions,  the  other  ion 
being  free  to  act  upon  more  difficultly  oxidisable 
substances  by  a  secondary  operation.  Another 
widely  different  theory  is  that  reducing  substances 
are  formed  by  the  protoplasm,  which  split  the  neutral 
oxygen  molecule,  uniting  with  one  and  setting  the 
other  free.  The  cells  of  animal  tissues  and  organs 
have  the  property,  like  the  cells  of  lower  organisms, 
of  splitting  dys-oxidisable  substances  into  such  as  are 
more  easily  oxidisable,  perhaps  with  the  production 
of  nascent  hydrogen.  The  oxidation  of  the  readily 
oxidisable  substances  as  produced  by  ionisation  of 
oxygen  leads  to  the  secondary  oxidation  of  the  less 
oxidisable  ones  ;  and  the  products  undergo  further 


OXIDASES  113 

cleavage  and  oxidation  until  they  arrive  at  the  final 
stage  of  metabolism. 

According  to  Traube,*  we  have  to  deal  in  the  first 
place  with  the  splitting  of  water  into  H  and  OH  ions. 
The  OH  ion  combines  with  and  oxidises  the  oxi- 
disable  substance  ;  while  the  H  ion  combines  with 
neutral  oxygen  to  form  peroxide  of  hydrogen  ;  the 
latter  again  having  an  oxidising  action.  It  is  known 
that  H  and  OH  ions  are  toxic  to  cellular  tissues,  and 
it  is  affirmed  by  Loew  that  certain  cellular  enzymes 
which  he  calls  catalases  protect  the  cell  from  the 
effects  of  these  ions. 

The  above  supposes  a  direct  oxidation  of  the 
primary  active  substance.  Animal  oxidations  may 
however  be  brought  about  by  oxygen-carriers,  or 
bodies  which,  without  being  oxidised  themselves, 
alternately  take  up  and  introduce  oxygen  into  sub- 
stances which  are  oxidised  with  difficulty  or  dys- 
oxidisable.  These  were  called  by  Traube  oxidation 
ferments  and  later  oxidases.  Little  is  known  about 
the  nature  or  action  of  ferments.  Some  however 
are  nucleo-proteids,  others,  like  the  catalases,  are 
proteoses,  while,  on  the  contrary,  liver-aldehyde  and 
laccase  are  not  of  a  proteid  nature.  Some  are  direct 
oxidases,  others  are  indirect  or  peri-oxidases.  They 
seem  to  have  a  pronounced  specific  action,  or  as 
Ehrlich  calls  it  monotropism,  that  is  to  say,  they  oxi- 
dise certain  substances  and  not  others.  Their  action 
is  not  well  understood,  but  it  is  a  catalysis,  produced 
by  intermediate  reactions.  Some  of  these  oxidases 
contain  iron  or  manganese,  and  as  these  salts  are 

*  Hammarsten's  "  Physiological  Chemistry,"  p.  6  (American 
Edition). 

8 


114  THE  THEORY  OF  IONS 

known  to  be  catalysers,  so  the  important  role  of 
oxygen-carrying  by  the  oxidases  has  been  ascribed 
to  these  salts. 

In  animal  organisms,  oxidation  has  been  looked 
upon  as  a  combustion  of  material.  This  comparison 
may  still  be  considered  to  hold  good.  In  the  com- 
bustion of  devitalised  organic  products,  such  as 
wood,  coal  or  oil,  there  is  first  a  decomposition  into 
other  substances  before  the  phenomenon  of  light  is 
produced.  In  the  living  organism,  chemical  energy 
is  transformed  into  heat  and  work  by  various  oxi- 
dations, whereby  there  is  a  cleavage  of  complex 
substances  into  simpler  and  more  stable  compounds. 
Such  a  decomposition  results  from  the  preliminary 
dissociation  of  water  into  H  and  OH  ions,  which 
react  upon  the  substance  to  be  decomposed  ;  it  is 
called  a  hydrolytic  cleavage,  e.g. — 

Tristearin  Glycerine          Stearic  acid 

C3H6(C18H3602)3  +  3H20  =  C3H5(OH)3  +  3C18H36O2. 

Such  cleavages  can  be  produced  outside  the  body 
by  means  of  acids  and  alkalies.  But  the  animal 
organism  has  a  better  way  of  producing  the  cleavage, 
and  that  is  by  means  of  the  enzymes  ;  such  as  the 
proteolytic,  amylolytic  and  lipolytic  enzymes  of  the 
alimentary  canal. 

The  action  of  the  enzymes  seems  to  depend  upon 
the  stereometric  construction  of  the  molecules  acted 
upon.  Each  acts  upon  a  special  kind  of  substance  or 
is  monotropic  ;  thus,  the  enzymes  of  yeast  act  only 
upon  a-glucosides,  while  emulsin  will  only  act  upon 
6-glucosides.  But  the  manner  of  their  action  is  still 
unknown.  Certain  work  done  by  Ikeda,  Bredig  and 


ENZYMES  115 

Reinders  upon  lipase,  invertase,  diastase  and  emul- 
sin,  shows  that  there  is  a  marked  correspondence 
between  catalysis  and  enzyme  action.  By  working 
with  inorganic  colloidal  solutions,  such  as  platinum 
and  gold,  Bredig  was  able  to  show  that  they  had  such 
a  strong  resemblance  to  the  action  of  enzymes  that 
he  called  them  inorganic  ferments.  This  corre- 
spondence has  led  to  the  idea  that  ferment  action  is 
due  to  the  play  of  electricity  which  comes  with  the 
metallic  ions  in  colloidal  solutions.  We  have  seen 
that  a  colloidal  solution  consists  of  very  fine  particles 
which  have  assumed  an  electrical  charge  through 
giving  off  ions,  just  as  have  electrodes.  In  con- 
sequence the  enzymes  act  pretty  much  like  elec- 
trodes. Some  of  these  ferments,  called  catalysers, 
determine  the  direction  of  a  reaction,  whether  it 
shall  be  oxidation  and  reduction  or  hydration  and 
splitting  off  of  water.  Such  catalysers  can  act  in 
two  directions,  depending  on  the  relationship  be- 
tween the  original  substance  and  those  to  be  formed. 
Amygdalin  can  be  split  into  amygdalic  nitril 
glucoside  and  glucose  under  the  influence  of  yeast- 
maltose  ;  it  can  also  be  rebuilt  from  these  con- 
stituents by  help  of  the  same  enzyme.  In  the  living 
organism  many  antagonistic  reactions  take  place 
under  the  influence  of  such  catalysers.  The  syn- 
thesis of  glycogen  from  dextrose,  and  the  splitting  of 
glycogen  into  dextrose,  represents  such  an  antago- 
nistic reaction,  in  which  the  dextrose  becomes  poly- 
merised into  glycogen,  with  loss  by  the  molecules  of 
H  and  OH  ions  ;  "  while  the  synthesis  of  starch  in 
plants  and  its  diastatic  splitting  into  glucose  or 
maltose  represents  a  heterodome  antagonistic  reac- 

8—2 


116  THE  THEORY  OF  IONS 

tion  in  which  the  synthesis  has  the  upper  hand  by 
day  and  the  analysis  by  night."* 

The  colloidal  constitution  of  living  matter  is  inti- 
mately connected  with  the  most  important  problems 
of  biological  chemistry.  Chemical  reactions  of  the 
most  different  character  are  simultaneously  possible 
in  the  colloidal  ground  substance  of  the  cell.  An- 
tagonistic reactions  such  as  oxidation  and  reduction, 
hydration  and  dehydration,  condensation  and  poly- 
merisation, synthesis  and  analysis,  go  on  almost  side 
by  side.  "  Just  as  the  chemist  allows  different 
chemical  reactions  to  take  place  in  different  vessels, 
the  cell  is  believed  to  utilise  the  different  chambers 
of  its  honeycomb  structure,  and,  with  the  aid  of 
colloidal  ferments,  allows  the  necessary  reactions  to 
go  on  independently  of  each  other,  "f  The  laws  of 
colloid  chemistry  govern  the  changes  that  go  on  in 
the  cells,  but  these  laws  are  modified  by  the  pro- 
cesses of  metabolism  and  their  variations  are  not 
clearly  understood.  In  the  cells  the  colloids  are 
more  or  less  jelly-like  or  in  the  condition  of  gels  ; 
but  in  the  tissue  juices  they  are  in  the  fluid  condi- 
tion and  are  called  sols. 

In  intra-cellular  substances  there  is  a  certain 
parallelism  between  the  changes  in  colloids  and  the 
cellular  manifestations,  such  as  in  swelling,  absorp- 
tion, movement,  and  the  effects  of  various  stimuli. 
But  the  extra-cellular  substances  of  living  organisms 
are  subject  to  direct  control  by  the  laws  of  colloidal 
chemistry,  as  investigations  have  shown.  A  study 
of  the  phenomena  exhibited  by  extra-cellular  col- 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  64.  t  Loc.  cit.,  p.  58. 


ANTIBODIES  117 

loids  is  therefore  of  importance  in  view  of  the 
modern  teachings  respecting  immunity. 

The  living  organism  produces  curative  or  protec- 
tive agents  in  the  blood,  antigens  and  antibodies. 
The  antigens  are  substances  which  give  rise  to  the 
antibodies.  Their  chemical  composition  is  un- 
known, but  they  have  a  colloidal  constitution.  The 
study  of  these  substances  was  begun  with  the  dis- 
covery of  antitoxins  by  von  Behring. 

The  antibodies,  such  as  antitoxin  and  anti- 
bacterial substances,  are  monotropic,  i.e.  "  they 
are  so  to  speak  charmed  bullets  which  strike  only 
those  objects  for  whose  destruction  they  have  been 
produced  by  the  organism,  and  they  are  directed 
against  bacteria  or  against  the  products  of  their 
metabolism  (toxins)  which  cause  disease."*  The 
cause  of  this  specificity  is  in  Ehrlich's  opinion  the 
effect  of  the  chemical  relation  which  exists  between 
the  infective  body  and  the  antibody.  They  fit  one 
another  as  a  key  fits  a  lock.  The  colloid  nature  and 
chemical  reactive  power  of  the  immune  substance 
do  not  exclude  one  another  ;f  for  colloids  possess 
certain  groups  of  atoms  which  render  them  capable 
of  reactions  of  a  synthetic  nature.  '  The  condition 
for  this  action  is  the  presence  of  two  groups,  whose 
chemical  relationship  is  of  the  closest  and  whose 
interaction  is  therefore  a  condition  of  their  union. 
This  action  as  to  union  is  the  basis  of  my  side-chain 
theory."J 

*  Ehrlich  :  "The  Harben  Lectures,"  Jour.  Roy.  Inst.  Pub. 
Health,  1907,  p.  323. 

f  Loc.  cit. 

+  Ehrlich:  "The  Harben  Lectures,"  Jour.  Hoy.  Inst.  Pub. 
Health,  p.  324, 


118  THE  THEORY  OF  IONS 

In  the  case  of  toxins,  there  must  be  a  connexion 
between  their  chemical  constitution  and  action,  just 
as  there  is  in  well-known  poisons.  In  cocaine  the 
anaesthetic  effect  is  due  to  the  benzoyl-radical,  which 
in  consequence  Ehrlich  calls  the  ancesthesiophore  ; 
the  soporific  effect  of  sulphonal  and  other  disulphons 
is  due  entirely  to  the  ethyl-radical ;  and  so  on. 
Similarly  there  is  in  the  toxin  a  group  which  causes 
the  peculiar  effect  of  the  toxin,  and  this  is  called  by 
Ehrlich  the  toxophore  group. 

But  the  toxophore  group  is  not  of  itself  sufficient 
to  bring  about  the  poisonous  action.  There  must 
be  some  peculiarity  of  the  toxin  which  causes  its 
distribution,  and  this  action  he  attributes  to  a 
haptophore  group.  Similarly  there  must  be  a  corre- 
sponding chemical  group  in  the  cellular  protoplasm 
which  reacts  with  them,  and  this  is  called  the 
receptor.  The  toxin  action  can  only  occur  when 
there  are  present  such  receptors  fitted  to  anchor 
the  toxins.  "  We  can  prove  the  existence  of 
receptors,"*  and  the  binding  action  or  anchoring 
of  toxins  by  such  receptors  plays  a  great  part  in 
immunity. 

In  order  that  the  poisonous  action  of  the  toxin 
may  take  place,  we  must  presume  not  only  the 
presence  of  fitting  receptors,  but  that  they  are 
present  in  a  position  favourable  for  the  toxic  action 
to  be  brought  about.  When  the  receptor  and  the 
organs  sensitive  to  the  action  of  the  toxin  are  present, 
the  conditions  for  infection  are  most  favourable  ; 
distribution  takes  place  at  once,  and  the  poison 

*  Ehrlich:  "The  Harben  Lectures,"  Jour.  Boy.  Inst.  Pub. 
Health,  p.  326. 


ANTIBODIES  119 

circulates  until  it  reaches  the  sensitive  cells.  When 
receptors  are  not  present  the  animal  possesses 
natural  immunity  ;  when  they  are  present  the  organ 
or  body  is  more  or  less  sensitive  to  the  poison,  and 
antibodies  are  formed.* 

According  to  the  views  of  Ehrlich,  antibodies  are 
purely  and  simply  receptors  fitted  for  union  with 
the  poison  ;  that  when  antitoxin  is  used  therapeuti- 
cally  we  are  merely  injecting  a  number  of  receptors 
which  will  reinforce  those  of  the  organism.  The 
toxins  are  anchored  to  such  receptors  by  the  hapto- 
phore  group  ;  and  when  they  have  anchored  the 
toxin,  the  work  of  the  receptors,  as  such,  is  done. 

All  antibodies  act  in  a  similar  way.  But  they 
have  another  action  upon  the  anchored  substance. 
This  action  may  be  direct,  as  in  the  case  of  the  pre- 
cipitins  and  agglutinins.  It  may,  however,  be  in- 
direct, as  in  the  case  of  the  opsonins,  which  render 
the  bacterial  cells  assimilable  by  phagocytes. 

There  is  another  class  of  antibodies  called  by 
Ehrlich  the  amboceptors.  They  are  present  in  the 
blood  serum  of  normal  animals,  and  are  of  various 
kinds.  They  are  considered  by  Ehrlich  to  play  an 
important  role  even  in  the  normal  condition.  "  I 
hold  that  this  function  in  physiological  life  is  that 
of  seizing  upon  and  elaborating  nutritive  sub- 
stances.'^ They  also  arise  as  a  new  formation 
during  the  process  of  immunisation.  J  They  are 
characterised  by  monotropism,  and  their  presence 
renders  the  cell  liable  to  the  action  of  a  toxin-like 

*  EhrlicK:  "The  Harben  Lectures,"  Jour.  Eoy.  Inst.  Pub. 
Health,  p.  326. 

Loc.  cit.  Loc.  cit. 


120  THE  THEORY  OF  IONS 

constituent  said  by  him  to  be  present  in  the  blood 
serum,  and  called  the  complement.  The  complement 
is  also  a  normal  constituent  of  the  blood  serum,  but 
has  no  direct  relation  to  the  cell.  It  is  harmless  by 
itself,  but,  like  toxin,  has  a  toxophore  and  a  hapto- 
phore  group.  The  amboceptor-laden  cell  is  exposed 
to  the  action  of  the  complement  of  the  serum,  and 
the  latter  acts  upon  the  cell  through  the  influence 
of  the  amboceptor.  Complement  and  amboceptor 
stand  in  a  direct  relation  to  one  another,  and  become 
anchored  together.  This  is  not  a  relationship  due 
to  a  maximum  chemical  affinity  ;  but  rather  a  loose 
relationship  with  perhaps  a  reversible  action. 

The  amboceptor  is  able  to  combine  with  substances 
of  the  most  varied  kind,  providing  they  possess 
fitting  receptors.  The  peculiar  power  of  the  ambo- 
ceptor to  fix  a  large  number  of  complements  is, 
therefore,  not  to  be  wondered  at.  But  if  the  entire 
mass  of  amboceptors  reacted  in  an  active  manner 
upon  the  entire  mass  of  the  complement,  the  latter 
would  all  be  anchored  to  the  complementophile 
group  of  the  amboceptors,  and  there  would  be  no 
free  complement  in  the  living  body.  This  would 
produce  a  grave  condition  of  affairs.  For  as  soon 
as  there  arose  occasion  for  the  action  of  comple- 
ments with  any  special  kind  of  amboceptor  there 
would  be  no  complement  available,  all  being  used 
up  by  the  action  of  indifferent  amboceptors.  It  is 
owing  to  the  fact  that  the  complements  are  free  or 
only  loosely  joined  to  amboceptors  that  they  are 
ready  for  use  at  any  given  moment.  The  maximum 
stimulus  to  action  is  made  possible  by  anchoring 
the  amboceptor  to  the  erythrocyte,  the  avidity  of 


IONS  IN  IMMUNITY  121 

which  for  the  complement  is  carried  to  the  maximum. 
The  amboceptor  exercises  the  function  of  bringing 
about  a  modification  of  the  conditions  which  deter- 
mine the  distribution  of  the  complement.  It  causes 
the  complements  to  become  monotropic  by  union 
with  its  substance  ;  and  the  complements  are 
localised  by  amboceptors  which  are  united  with 
some  other  substance  such  as  the  cells.  Such  is 
the  amboceptor  theory  of  Ehrlich. 

That  the  proteid  substances  are  able  to  act  upon 
one  another  is  undoubted.  But  all  authorities  are 
not  agreed  upon  the  foregoing  explanation.  Ehrlich's 
theories  are  not  accepted  without  an  attempt  being 
made  to  render  the  subject  somewhat  clearer.  This 
attempt  is  made  through  the  study  of  the  action  of 
ions  upon  colloids  and  by  the  laws  of  colloidal 
chemistry  ;  to  which  we  must  now  return, 

"  Let  us  suppose  that  a  sufficient  number  of  ions 
are  introduced  into  a  colloidal  solution  of  a  metal, 
which  represents  a  suspension  of  weakly  charged 
electro-negative  particles.  In  consequence  of  elec- 
trical attraction,  the  negative  colloidal  particles  will 
collect  about  the  electro-positive  ions,  until,  through 
the  heaping  up  of  a  sufficient  number  of  such  par- 
ticles, the  collecting  ions  will  be  electrically  neutral- 
ised. When  the  aggregates  thus  formed  have 
reached  a  sufficient  size,  the  solution  becomes  turbid 
and  finally  a  precipitate  drops  to  the  bottom."* 
According  to  the  ionic  theory  a  similar  process  takes 
place  in  the  reactions  of  precipitins,  agglutinins,  and 
probably  the  antitoxins. 

*  Pauli's  "Physical  Chemistry  in  the  Service  of  Medicine," 
p.  109, 


122  THE  THEORY  OF  IONS 

Just  as  there  are  colloids  which  carry  an  electro- 
negative charge,  so  there  are  others  which  carry  a 
positive  charge  ;  and  each  kind  will  be  precipitated 
by  an  oppositely  charged  ion  or  colloid.  Oppositely 
charged  colloids  will  precipitate  one  another,  just 
as  the  ions  of  salts  precipitate  colloids  ;  and,  owing 
to  the  greater  size  of  the  meres  or  colloidal  particles, 
the  conditions  for  the  formation  of  large  aggregates 
are  very  favourable.  In  this  again  we  see  the  im- 
portance of  the  ionic  theory.  A  study  of  the  pheno- 
mena exhibited  by  the  extra-cellular  colloids  in  the 
light  of  this  theory  will,  it  is  hoped,  throw  more 
light  upon  the  immunity  reactions.  How  these  are 
brought  about  is  by  no  means  yet  clear  to  us.  But 
colloids  undergo  changes,  not  only  by  reacting  upon 
one  another,  but  by  giving  off  ions,  as  we  have 
already  seen.  Indeed,  colloidal  particles  become 
remarkably  changed  by  the  loss  of  a  side-chain  or 
a  few  atoms  from  the  molecule.  As  the  colloidal 
particles  grow  smaller  by  this  loss  of  side-chains  or 
ions,  their  electrical  charge  grows,  and  they  approxi- 
mate more  and  more  to  the  nature  of  ions,  until, 
finally,  the  colloid  may  pass  over  by  dissociation  in 
the  solution  into  strongly  charged  ions.*  The  con- 
verse of  this  is  possible  and  probably  takes  place 
in  the  reconstruction  of  the  digested  and  assimilated 
nutritive  particles  into  the  colloidal  material  of 
proteids,  carbohydrates  and  fats. 

An  important  point  in  connexion  with  the  pre- 
cipitins  is  that  the  precipitation  of  colloids  is  only 
possible  in  the  presence  of  salts.  If  for  instance  the 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  120. 


IONS  IN  IMMUNISATION  123 

proteins  or  bacteria  under  investigation  are  mixed 
with  the  specific  substance  under  consideration  in 
a  salt-free  condition  no  reaction  occurs.  The  specific 
substances  may  therefore  be  looked  upon  as  giving 
to  the  colloidal  protein  the  properties  of  sensitive 
colloids,  and  of  being  precipitated  through  the 
presence  of  a  small  amount  of  salt-ions.* 

Again  :  two  reacting  colloids  show  an  optimum 
for  precipitation,  and  an  inhibition  of  the  precipi- 
tating process  when  one  is  in  excess.  This  is  a 
generalised  phenomenon  of  colloids  in  agglutination, 
and,  according  to  Biltz,  is  observed  in  nearly  all 
immune-body  reactions.  The  bacterial  antitoxin 
sera  show  a  maximum  effect  when  they  contain  a 
medium  amount  of  the  immunising  substance. 

The  proteins,  including  the  antibodies,  according 
to  Landsteiner,  represent  amphoteric  substances  ; 
that  is,  substances  which  assume  basic  properties  in 
acid  substances  and  acid  properties  in  alkaline  solu- 
tions ;  they  change  the  sign  of  their  electrical  charge 
with  a  change  in  their  reaction.  "  But  there  exists 
a  zone  between  the  extreme  changes  of  their  elec- 
trical charges  when  these  hermaphrodite-like  sub- 
stances respond  to  the  slightest  change  in  their  sur- 
roundings." That  these  normally  sensitive  colloids 
have  at  one  time  a  positive  and  at  another  time  a 
negative  kind  of  electricity  is  evident  from  facts  ; 
and  Landsteiner's  attempt  to  explain  the  specificity 
of  antibodies  is  based  upon  his  conception  of  the 
role  played  by  these  amphoteric  substances. 

The  side-chain  theory  of  Ehrlich,  developed  by 

*  Pauli's  "  Physical  Chemistry  in  the  Service  of  Medicine," 
p.  123. 


124  THE  THEORY  OF  IONS 

him  to  explain  his  views  of  immunity,  does  not  satisfy 
all  the  conditions.  He  has  utilised  the  fact  that 
the  affinity  of  toxin  for  antitoxin,  and  the  toxicity 
of  toxins,  vary  independently  of  each  other  to  sup- 
port the  idea  that  each  contains  a  toxophore  and  a 
haptophore  group,  which  supply  the  materials  for 
the  reaction.  But  Arrhenius,  Gruber,  Pauli,  and 
others,  who  seek  for  an  explanation  of  the  facts  by 
the  light  of  the  ionic  theory,  consider  that  toxin  and 
antitoxin  consist  of  a  mixture  of  compounds  which 
have  a  weak  affinity  for  each  other ;  and  that 
Ehrlich's  assumptions  are  not  supported  by  the  facts 
of  colloidal  chemistry. 

It  is  through  a  study  of  colloidal  chemistry  that 
we  may  also  expect  to  find  an  explanation  of  extra- 
cellular phenomena  such  as  the  development  of  .car- 
tilage and  bone,  and  the  precipitation  of  crystalline 
substances  in  these  and  other  tissues.  The  nucleus 
of  the  question  consists  of  the  fact  that  we  are 
dealing  on  the  one  hand  with  the  simple  process 
of  crystallisation,  and  on  the  other  with  the  forma- 
tive influence  of  the  cells  and  forces  destined  to  act 
upon  them.  The  colloids  constitute  an  excellent 
means  of  keeping  slightly  soluble  salts  in  solution, 
under  certain  circumstances,  by  uniting  with  the 
ions  of  the  salts  to  form  aggregates  which  in  the  case 
of  protein  are  not  necessarily  precipitated  (vide  ante). 
If  however  through  some  influence,  such  as  meta- 
bolism, the  dissolving  protein  is  destroyed,  a  pre- 
cipitation of  the  colloidal  material  may  occur. 
Crystals  being  once  formed  may  serve  for  centres  of 
continued  crystallisation.  It  is  in  such  a  conception 
of  the  vital  activities  of  the  cell  and  cystallisation 


CONCLUSION  125 

that  we  may  expect  to  find  an  explanation  of  the 
pathological  processes  of  calcification  and  deposition 
of  uric  acid,  or  on  the  other  hand  the  physiological 
calcification  and  ossification  which  occur  as  a  result 
of  the  metabolism  of  the  tissues. 

The  theory  of  ions,  nascent  or  unattached  meres 
of  substances  having  an  electrical  reaction  and 
arising  from  molecular  forms  of  matter  by  dissocia- 
tion, is,  from  the  view  taken  in  the  foregoing  pages, 
extremely  important.  Whether  it  is  possible  to 
construct  a  working  hypothesis  of  life  upon  it 
appears  quite  probable  in  the  light  of  recent  progress 
in  electro-biology  and  bio-chemistry.  The  time  has 
not  yet  arrived  when  we  can  say  exactly  what  life  is 
or  what  constitutes  the  difference  between  dead  and 
living  matter,  although  the  question  has  been  con- 
sidered philosophically  for  centuries.  Important  as 
ionisation  is  in  constructive  and  destructive  pro- 
cesses there  must  be  something  which  initiates  those 
processes,  some  at  present  unknown  cause  of  their 
continuance.  The  riddle  of  contractility  still 
remains  unsolved.  What  is  defined  as  life  is  the 
product  of  all  the  forces  acting  in  an  organism,  but 
the  fons  et  origo  from  which  these  forces  are  initiated 
is  still  an  unknown  quantity.  When  a  child  is  fed 
on  milk,  the  proteins  are  first  split  up  by  the  ali- 
mentary enzymes  into  ions  or  some  analogous  forms 
of  matter  in  an  active  state  which  may  be  called 
meres.  While  in  this  active  condition  they  are 
ready  for  union  with  other  ions,  meres,  or  analogous 
forms  of  matter,  to  construct  new  protein  molecules 
or  to  be  reduced  to  a  lower  grade  of  chemical  con- 
stitution on  their  way  to  urea.  When  a  cell  makes 


126  THE  THEORY  OF  IONS 

use  of  serum-protein  for  the  formation  of  its  own 
special  proteins,  the  serum-protein  is  first  broken 
down  into  fragments  which  consist  mainly  of 
amino-acids.  How  is  protein  reconstructed  ?  We 
must  either  admit  that  matter  may  be  in  two  forms 
— active  and  passive — or  we  must  assume  that  a  dis- 
tinct vital  principle  is  involved  in  the  process  of 
reconstruction.  If  we  admit  that  matter  about  to 
undergo  construction  into  molecules  of  something 
else  is  in  an  active  form,  such  as  ions,  or  meres 
analogous  to  them,  it  would  be  difficult  to  draw  a 
line  between  the  activity  of  ions  in  electrolytic  con- 
duction and  such  matter  in  the  course  of  construc- 
tion into  fat  or  cellular  protein.  It  is  the  old 
question  of  a  vital  principle  as  distinct  from 
chemical  force  or  physical  energy.  What  is  it 
renders  the  matter  active,  which  enables  ions  or 
meres  to  form  organic  substances,  which  produces 
will  and  reason  ?  The  vitalist  argues  that  it  is  a 
vital  force  which  mysteriously  moulds  the  elements 
into  organic  tissues,  the  tissues  into  organs,  and  the 
organs  into  an  organism.  The  physicist  says  life  is 
the  sum  of  the  particular  vital  activities  exhibited  by 
an  organism.  According  to  the  first  theory  it  is 
antecedent  to  and  the  source  of  all  vital  phenomena  ; 
according  to  the  latter  it  is  the  result  of  the  numerous 
activities  exhibited  by  an  organism  and  dependent 
upon  various  forces.  Life  is  the  result  of  the  com- 
munication of  motion  to  previously  inert  matter,  a 
transformation  from  passivity  to  activity,  and  the 
conversion  of  that  activity  to  a  particular  mode  of 
action,  whether  it  be  dominated  by  blind  energy  or 
a  purposive  and  intelligent  force. 


CONCLUSION  127 

In  writing  Finis  to  this  little  work  I  gratefully 
acknowledge  the  amount  of  information  derived 
from  the  many  sources  quoted.  Especially  do  I 
acknowledge  the  free  use  I  have  made  of  Pauli's 
valuable  "  Physical  Chemistry  in  the  Service  of 
Medicine,"  of  Hammarsten's  "  Physiological  Chem- 
istry," Newth's  "Inorganic  Chemistry,"  Holler's 
"  Chemistry,"  Morgan's  "  Physical  Chemistry,"  and 
several  other  works.  According  to  the  conception 
of  natural  phenomena  in  these  works,  transformation 
of  energy  forms  the  kernel  of  all  phenomena  in 
Nature.  This  principle  however  has  not  yet  solved 
the  problem  of  life  phenomena  and  has  merely 
touched  the  fringe  of  that  subject,  great  as  must  be 
acknowledged  is  the  progress  that  has  been  made  in 
many  departments.  While  physicists  alone  have  been 
unable  to  exhaust  the  problem  of  life,  the  teaching 
of  a  vital  force  is  again  to  the  fore  ;  and  the  neo- 
vitalists,  tracing  back  their  theory  to  the  anima  of 
Georg  Ernst  Stahl,  urge  that  vital  force  alone  can 
account  for  the  phenomena  of  vitality.  It  requires 
care  in  the  employment  of  the  ionic  theory  to  the 
explanation  of  vital  phenomena  not  to  mistake  "  the 
death-dance  of  the  molecules  "  for  living  vitality. 
The  assertion  of  Ostwald  that  we  react  only  in  pro- 
portion to  differences  in  energy  also  requires  limita- 
tion ;  for  there  is  little  doubt  that  at  different  times 
we  react  differently  to  the  same  degree  and  kind  of 
stimulus.  The  quality  of  the  stimulus  is  as  impor- 
tant as  its  quantity  ;  noise  is  not  music  necessarily, 
although  the  same  amount  of  energy  may  be  ex- 
hausted in  producing  the  vibration. 

It  may  be  that  belief  in  a  vital  force  will  continue. 


128  THE  THEORY  OF  IONS 

It  will  only  bow  to  the  laws  of  energy,  and  cease  to 
exist  when  our  knowledge  of  natural  phenomena  has 
reached  a  higher  level  than  at  present.  This  know- 
ledge can  only  be  gained  through  more  exhaustive 
research  in  organic  domains  by  the  aid  of  bio- 
chemistry, and  further  dynamical  research  into  the 
relations  of  matter  and  force.  There  are  forces  at 
present  only  vaguely  understood,  forms  of  matter  so 
subtle  that  it  is  almost  impossible  to  say  they  are 
material.  There  are  forms  of  matter,  like  radium, 
from  which  inconceivably  minute  particles  radiate 
at  a  velocity  of  two  thousand  miles  a  second,  and  the 
exhaustion  of  a  minute  grain  of  which  would  occupy 
millions  of  years.  The  energy  radiating  from  such 
matters  is  exceedingly  great ;  and  our  knowledge  of 
such  substances  is  very  recent.  As  knowledge  pro- 
gresses other  forms  of  force  not  yet  known  or  under- 
stood may  come  within  our  cognisance  and  help  to 
make  clear  the  subject  of  vitality.  It  is  conceivable 
that  matter  is  energy  in  another  form.  That  the 
energy  which  renders  matter  active  and  capable  of 
uniting  into  organic  molecules  arises  by  the  trans- 
formation of  energy  possessed  by  infinitesimal  par- 
ticles radiating  throughout  the  universe.  If  energy 
is  not  matter  in  another  form,  it  is  so  closely  asso- 
ciated with  it  that  one  might  almost  say  that  force 
is  indissoluble  from  matter ;  that  where  matter  is, 
there  also  is  energy  ;  and  that  the  more  complex  the 
molecules  become  the  higher  is  the  form  of  force 
associated  with  the  material  forming  them,  and  so 
from  ions  which  convey  electricity  matter  passes 
through  various  stages  of  activity,  until  it  reaches 
the  highest  form  in  the  cells  of  the  nervous  system. 


INDEX 


ABEGG~on  formation  of  ions,  16 
Absorption  of  ions,  21,  32 
Acids,  59 

Affinity  of  matter,  48 
Amboceptor  theory,  117 
Amides,  68 
Amines,  66 
Amino-acids,  42,  67 

Emmerling  on  the,  41 
Amphoteric  substances,  123 
Anaesthetic  ions,  101 
Anions,  17,  49 
Antagonism  of  ions,  97,  102 
Antibodies,  117 
Application  of  ions,  direct,  108 
Atom  as  a  system,  the,  6 
Atomic  theory,  1 
Atoms,  chain  theory  of,  52 

vortex  theory  of,  46 

Bacteria,  effects  of  ions  upon, 

107 

Barker  on  amino-acids,  42 
Bein,  influence  of  septa  on  ions, 

20 
Biogens,  76 

Calcification,  124 
Carbohydrates,  evolution  of,  53 
Catalases,  113  ^  ,d  ^  -ss^ 
Cations,  17,  49  fflMfPlHP  ** 
Cells,    electric   reaction   due   to 

ions,  95  &i 
Chain  theory,  52 
Cholin,  69 
Colloidal  constitution  of  living 

matter,  85 
Colloids,  83 


Colloids,  action  of  ions  on,  88 

animals  dependent  on,  88 
Condensation  theory,  2 
Contractility  influenced  by  ions, 

23,29 
Constructive  processes  in  plant ;, 

34 

Cyanhydrines,  77 
Cyanogen  compounds,  77 
Cyanogen      theory      of      living 

matter,  77 

Dissociation,  12 

Diureides,  72 

Electrical  potential  due  to  ions, 

81,  92 

Electricity  conveyed  by  ions,  17 
Electrolytes,  13 
Electrons,  5 
Enzymes,  88,  114 
Erhlich  on  immunity,  117 
Esters  and  ions,  100 
Evolution  of  organic  matter,  46 
Excretion  of  metals,  99 

Fats,  evolution  of,  59 
Fischer  on  proteins,  40 
Functions  influenced  by  ions,  21, 
29 

Globulins,   solution   of,   due   to 

ions,  81,  88 
Glucosamine,  55 
Graham  on  colloids,  83 
Growth  influenced  by  ions,  24, 

104 


129 


9 


130 


INDEX 


Halogens,  the,  61 
Heart,  effect  of  ions  upon  the,  28 
Heat  due  to  ionisation,  26,  36 
Howell  on  the  heart,  29 
Hydrocarbons,  evolution  of,  57 
Hydroxyl,  effect  on  growth,  106 
Hydroxylamine,  39,  66 

Imides,  68 

Immunity  and  oxidation,  111 

Ions,  the,  12 

absorption  of,  21 

and  esters,  100 

and  lipoids,  100 

and  oxidation,  111 

antagonism  of,  90,  97,  102 

anions,  17 

applied  in  therapeutics,  108 

conduct  electricity,  17 

effect  on  contractility,  23,  29 
on  growth,  24,  104 
on  the  heart,  28,  105 
on    micro-organisms, 

107 

on  the  organism,  80 
on  proteins,  85,  94 
on  taste,  22 
physiological,  of,  96 

essential   to   the   organism, 
90,92 

give  the  electrical  charge,  92 

how  formed,  12 

hydroxyl,  effect  on  growth, 
106 

in  biology,  30 

in  immunity,  111,  121 

in  pharmacology,  96 

in  plants,  31 

their  electric  charge,  17 

their  reaction,  17 

their  valency,  49 

their  velocity,  18 
Ion-protein  compounds,  89 

Kalenberg  on  taste  due  to  ions, 

22 
Kinetic  theory,  1 

Lecithin,  formation  of,  51 
Lipoids  and  ions,  100 


Living  matter,  30,  73 

characters  of,  7 
evolution  of,  46 
instability  of,  76 
Pfliiger's  theory  of,  77 

Loeb  on  contractility,  27 

Matter,  affinity  of,  46 

polarity  of,  47 

theories  of,  2 

valency  of,  49 
McKenclrick  on  life,  30 
Meres,  12,  84 
Metabolons,  5 
Metals,  excretion  of,  98 
Micro-organisms,  effect  of  ions 

on,  107 
Millikin  and  Stiles  on  action  of 

ions,  27 
Mineral  constituents  of  body  are 

ions,  81 
Muscular  activity  and  ions,  25 

Nageli  on  living  substance,  30 
Nitrogen  compounds,  64 
Non-electrolytes,  13 

cannot  displace  ions,  92 

Osmotic  pressure  due  to  ions,  19 
Ostwald  on  reaction,  127 

on  permeability  of  cells,  96 
Oxidases,  113 
Oxidation  and  ions,  111 

Pauli  on  electrical  charge  of  pro- 
teins, 94 
on  ions  and  lipoids,  100 

in  immunity,  121 
on  living  matter,  86 
on  physiological  effects   of 

ions,  96 

on  sulphocyanates,  100 
Permeability  of  cells  to  ions,  95 
Pfliiger's  theory  of  living  matter, 

77 

Phosphorus  compounds,  61 
Physiological  effect  of  ions,  96 
Polarity  of  matter,  47 
Proteids,  evolution  of,  43 


INDEX 


131 


Protein-ion  compounds,  89,  92 
Proteins,  39 

construction  of,  42 

electrical  charge  due  to  ions, 
92 

kept  in  solution  by  ions,  81, 
88 

Pauli  on,  85,  89,  94 

synthesis  of,  64 
Protoplasm,  effect  of  ions  on,  23 

Radio-active  bodies,  5 
Receptors,  117 
Richards  on  taste,  22 

Sugar  formation,  54 
Sulphur  compounds,  63 
Synthetic  processes  in  plants,  41, 
53 

Taste  due  to  ions,  22 
Therapeutics,  ions  in,  96,  108 


Theory  of  amboceptors,  117 

of  atoms,  1 

chain,  the,  52 

condensation,  2 

kinetic,  2 

Pfliiger's,  77 

vortex-atom,  46 
Toxicity  of  ions,  23,  104 
Traube    on    oxidation    in    the 

tissues,  113 

Urea,  70 
Uric  acid,  72 

Valency  of  the  atoms,  49 
Variability  of  electric  reaction, 

95 

Verworn  on  living  matter,  76 
Vital  force,  10,  126 
Vitalism,  125 
Vogt's  theory  of  matter,  2 
Vortex-atom  theory,  46 


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THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


Tibbies,  T.V 
The  theory 


lliam. 
of  ions 


1815 


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